Fixes some capitalization

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>net.knarcraft</groupId>
     <artifactId>BooksWithoutBorders</artifactId>
-    <version>1.3.8</version>
+    <version>1.3.9-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <licenses>

src/main/java/net/knarcraft/bookswithoutborders/BooksWithoutBorders.java

@@ -18,11 +18,13 @@ import net.knarcraft.bookswithoutborders.command.CommandSave;
 import net.knarcraft.bookswithoutborders.command.CommandSavePublic;
 import net.knarcraft.bookswithoutborders.command.CommandSetAuthor;
 import net.knarcraft.bookswithoutborders.command.CommandSetBookPrice;
+import net.knarcraft.bookswithoutborders.command.CommandSetBookshelfData;
 import net.knarcraft.bookswithoutborders.command.CommandSetGeneration;
 import net.knarcraft.bookswithoutborders.command.CommandSetLore;
 import net.knarcraft.bookswithoutborders.command.CommandSetTitle;
 import net.knarcraft.bookswithoutborders.command.CommandUnSign;
 import net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig;
+import net.knarcraft.bookswithoutborders.handler.BookshelfHandler;
 import net.knarcraft.bookswithoutborders.listener.BookEventListener;
 import net.knarcraft.bookswithoutborders.listener.BookshelfListener;
 import net.knarcraft.bookswithoutborders.listener.PlayerEventListener;
@@ -39,12 +41,15 @@ import org.bukkit.inventory.ItemFactory;
 import org.bukkit.plugin.PluginDescriptionFile;
 import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.java.JavaPlugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.UUID;
 import java.util.logging.Level;
 
@@ -59,16 +64,20 @@ import static net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig
 public class BooksWithoutBorders extends JavaPlugin {
 
     private static ItemFactory itemFactory;
-    private static Map<UUID, List<String>> playerBooksList;
+    private static @NotNull Map<UUID, List<String>> playerBooksList = new HashMap<>();
-    private static List<String> publicBooksList;
+    private static @NotNull List<String> publicBooksList = new ArrayList<>();
+    private static Map<Character, Integer> publicLetterIndex;
+    private static Map<UUID, Map<Character, Integer>> playerLetterIndex;
     private static BooksWithoutBorders booksWithoutBorders;
     private static ConsoleCommandSender consoleSender;
+    private static BookshelfHandler bookshelfHandler;
 
     /**
      * Gets the console sender for printing to the console
      *
      * @return <p>The console's console sender</p>
      */
+    @NotNull
     public static ConsoleCommandSender getConsoleSender() {
         return consoleSender;
     }
@@ -80,36 +89,70 @@ public class BooksWithoutBorders extends JavaPlugin {
      * @param getPublic <p>Whether to get available public books</p>
      * @return <p>A list of available books</p>
      */
-    public static List<String> getAvailableBooks(CommandSender sender, boolean getPublic) {
+    @NotNull
+    public static List<String> getAvailableBooks(@NotNull CommandSender sender, boolean getPublic) {
         if (getPublic) {
             return new ArrayList<>(publicBooksList);
         } else if (sender instanceof Player player) {
             UUID playerUUID = player.getUniqueId();
             if (!playerBooksList.containsKey(playerUUID)) {
                 List<String> newFiles = BookFileHelper.listFiles(sender, false);
+                if (newFiles != null) {
                     playerBooksList.put(playerUUID, newFiles);
+                    playerLetterIndex.put(playerUUID, BookFileHelper.populateLetterIndices(newFiles));
                 }
-            return playerBooksList.get(playerUUID);
+            }
+            return new ArrayList<>(playerBooksList.get(playerUUID));
         } else {
             return new ArrayList<>();
         }
     }
 
+    /**
+     * Gets the letter index map for public books, or a specific player's books
+     *
+     * @param playerIndex <p>The player to get the index for, or null for the public index</p>
+     * @return <p>An index mapping between a character and the first index containing that character</p>
+     */
+    @NotNull
+    public static Map<Character, Integer> getLetterIndex(@Nullable UUID playerIndex) {
+        if (playerIndex == null) {
+            return publicLetterIndex;
+        } else {
+            Map<Character, Integer> letterIndex = playerLetterIndex.get(playerIndex);
+            return Objects.requireNonNullElseGet(letterIndex, HashMap::new);
+        }
+    }
+
     /**
      * Updates available books
      *
      * @param sender       <p>The sender to update books for</p>
      * @param updatePublic <p>Whether to update public books</p>
      */
-    public static void updateBooks(CommandSender sender, boolean updatePublic) {
+    public static void updateBooks(@NotNull CommandSender sender, boolean updatePublic) {
         List<String> newFiles = BookFileHelper.listFiles(sender, updatePublic);
+        if (newFiles == null) {
+            return;
+        }
         if (updatePublic) {
             publicBooksList = newFiles;
+            publicLetterIndex = BookFileHelper.populateLetterIndices(newFiles);
         } else if (sender instanceof Player player) {
             playerBooksList.put(player.getUniqueId(), newFiles);
+            playerLetterIndex.put(player.getUniqueId(), BookFileHelper.populateLetterIndices(newFiles));
         }
     }
 
+    /**
+     * Clears book data such as per-player lists and per-player character indexes
+     */
+    public static void clearBookData() {
+        playerBooksList = new HashMap<>();
+        playerLetterIndex = new HashMap<>();
+    }
+
+
     @Override
     public void onEnable() {
         FileConfiguration config = this.getConfig();
@@ -123,8 +166,15 @@ public class BooksWithoutBorders extends JavaPlugin {
         booksWithoutBorders = this;
         consoleSender = this.getServer().getConsoleSender();
         playerBooksList = new HashMap<>();
+        playerLetterIndex = new HashMap<>();
         BooksWithoutBordersConfig.initialize(this);
-        publicBooksList = BookFileHelper.listFiles(consoleSender, true);
+        @Nullable List<String> files = BookFileHelper.listFiles(consoleSender, true);
+        if (files != null) {
+            publicBooksList = files;
+            publicLetterIndex = BookFileHelper.populateLetterIndices(files);
+        }
+        bookshelfHandler = new BookshelfHandler();
+        bookshelfHandler.load();
 
         PluginManager pluginManager = this.getServer().getPluginManager();
 
@@ -148,6 +198,7 @@ public class BooksWithoutBorders extends JavaPlugin {
      *
      * @return <p>An instance of this plugin</p>
      */
+    @NotNull
     public static BooksWithoutBorders getInstance() {
         return booksWithoutBorders;
     }
@@ -178,6 +229,7 @@ public class BooksWithoutBorders extends JavaPlugin {
         registerCommand("formatBook", new CommandFormat());
         registerCommand("setBookGeneration", new CommandSetGeneration());
         registerCommand("clearBook", new CommandClear());
+        registerCommand("setBookshelfData", new CommandSetBookshelfData());
     }
 
     /**
@@ -186,7 +238,7 @@ public class BooksWithoutBorders extends JavaPlugin {
      * @param commandName <p>The name of the command to register</p>
      * @param executor    <p>The executor to register for the command</p>
      */
-    private void registerCommand(String commandName, CommandExecutor executor) {
+    private void registerCommand(@NotNull String commandName, @NotNull CommandExecutor executor) {
         PluginCommand pluginCommand = this.getCommand(commandName);
         if (pluginCommand != null) {
             pluginCommand.setExecutor(executor);
@@ -222,11 +274,21 @@ public class BooksWithoutBorders extends JavaPlugin {
         return testFileSaving();
     }
 
+    /**
+     * Gets the bookshelf handler
+     *
+     * @return <p>The bookshelf handler</p>
+     */
+    public static BookshelfHandler getBookshelfHandler() {
+        return bookshelfHandler;
+    }
+
     /**
      * Gets the server's item factory
      *
      * @return <p>The server's item factory</p>
      */
+    @NotNull
     public static ItemFactory getItemFactory() {
         return itemFactory;
     }
@@ -270,7 +332,7 @@ public class BooksWithoutBorders extends JavaPlugin {
      * @param sender  <p>The sender to send the message to</p>
      * @param message <p>The message to send</p>
      */
-    public static void sendSuccessMessage(CommandSender sender, String message) {
+    public static void sendSuccessMessage(@NotNull CommandSender sender, @NotNull String message) {
         sender.sendMessage(getSuccessColor() + message);
     }
 
@@ -280,7 +342,7 @@ public class BooksWithoutBorders extends JavaPlugin {
      * @param sender  <p>The sender to send the message to</p>
      * @param message <p>The message to send</p>
      */
-    public static void sendErrorMessage(CommandSender sender, String message) {
+    public static void sendErrorMessage(@NotNull CommandSender sender, @NotNull String message) {
         sender.sendMessage(getErrorColor() + message);
     }
 

src/main/java/net/knarcraft/bookswithoutborders/command/CommandBooksWithoutBorders.java

@@ -24,7 +24,7 @@ import static net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig
 public class CommandBooksWithoutBorders implements TabExecutor {
 
     @Override
-    public boolean onCommand(CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
         sender.sendMessage(getCommandColor() + "[] denote optional parameters");
         sender.sendMessage(getCommandColor() + "<> denote required parameters");
         sender.sendMessage(getCommandColor() + "{} denote required permission");
@@ -42,7 +42,7 @@ public class CommandBooksWithoutBorders implements TabExecutor {
      *
      * @param sender <p>The console which sent the command</p>
      */
-    private void showConsoleCommands(CommandSender sender) {
+    private void showConsoleCommands(@NotNull CommandSender sender) {
         sender.sendMessage(getCommandColor() + "Commands:");
         showCommandInfo("deletePublicBook", sender);
         showCommandInfo("givePublicBook", sender);
@@ -54,7 +54,7 @@ public class CommandBooksWithoutBorders implements TabExecutor {
      *
      * @param sender <p>The player which sent the command</p>
      */
-    private void showPlayerCommands(CommandSender sender) {
+    private void showPlayerCommands(@NotNull CommandSender sender) {
         //Lists all commands
         Material bookPriceType = BooksWithoutBordersConfig.getBookPriceType();
         double bookPriceQuantity = BooksWithoutBordersConfig.getBookPriceQuantity();
@@ -69,6 +69,7 @@ public class CommandBooksWithoutBorders implements TabExecutor {
         }
         sender.sendMessage(getCommandColor() + "Commands:");
 
+        showCommandInfo("booksWithoutBorders", sender);
         showCommandInfo("copyBook", sender);
         showCommandInfo("decryptBook", sender);
         showCommandInfo("deleteBook", sender);
@@ -89,6 +90,8 @@ public class CommandBooksWithoutBorders implements TabExecutor {
         showCommandInfo("setLore", sender);
         showCommandInfo("setTitle", sender);
         showCommandInfo("unsignBook", sender);
+        showCommandInfo("clearBook", sender);
+        showCommandInfo("setBookshelfData", sender);
     }
 
     /**
@@ -97,7 +100,7 @@ public class CommandBooksWithoutBorders implements TabExecutor {
      * @param command <p>The command to get information about</p>
      * @param sender  <p>The sender asking to see command info</p>
      */
-    private void showCommandInfo(String command, CommandSender sender) {
+    private void showCommandInfo(@NotNull String command, @NotNull CommandSender sender) {
         PluginCommand pluginCommand = BooksWithoutBorders.getInstance().getCommand(command);
         if (pluginCommand != null) {
             String permission = pluginCommand.getPermission();
@@ -116,7 +119,8 @@ public class CommandBooksWithoutBorders implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
         return new ArrayList<>();
     }
 

src/main/java/net/knarcraft/bookswithoutborders/command/CommandClear.java

@@ -51,7 +51,7 @@ public class CommandClear implements TabExecutor {
     @Nullable
     @Override
     public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-                                      @NotNull String[] args) {
+                                      @NotNull String[] arguments) {
         return new ArrayList<>();
     }
 

src/main/java/net/knarcraft/bookswithoutborders/command/CommandCopy.java

@@ -26,7 +26,8 @@ import java.util.Objects;
 public class CommandCopy implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
@@ -37,14 +38,14 @@ public class CommandCopy implements TabExecutor {
             return false;
         }
 
-        if (args.length < 1) {
+        if (arguments.length < 1) {
             BooksWithoutBorders.sendErrorMessage(player, "You must specify the number of copies to be made!");
             return false;
         }
 
         try {
             ItemStack heldBook = InventoryHelper.getHeldBook(player, true);
-            int copies = Integer.parseInt(args[0]);
+            int copies = Integer.parseInt(arguments[0]);
             if (copies <= 0) {
                 throw new NumberFormatException("Number of copies must be larger than 0");
             }
@@ -64,7 +65,7 @@ public class CommandCopy implements TabExecutor {
      * @param heldBook <p>The book to be copied</p>
      * @return <p>True if the copying was successful</p>
      */
-    private boolean performCopy(int copies, Player player, ItemStack heldBook) {
+    private boolean performCopy(int copies, @NotNull Player player, @NotNull ItemStack heldBook) {
         //Make sure the player owns the book if authorOnlyCopy is enabled
         if (BooksWithoutBordersConfig.getAuthorOnlyCopy() &&
                 !player.hasPermission("bookswithoutborders.bypassAuthorOnlyCopy")) {
@@ -95,7 +96,7 @@ public class CommandCopy implements TabExecutor {
      * @param copies <p>The number of copies to create for the player</p>
      * @return <p>True if the payment failed</p>
      */
-    private boolean paymentUnSuccessful(Player player, int copies) {
+    private boolean paymentUnSuccessful(@NotNull Player player, int copies) {
         return BooksWithoutBordersConfig.booksHavePrice() &&
                 !player.hasPermission("bookswithoutborders.bypassBookPrice") &&
                 EconomyHelper.cannotPayForBookPrinting(player, copies);
@@ -109,7 +110,7 @@ public class CommandCopy implements TabExecutor {
      * @param copies   <p>The number of copies requested</p>
      * @return <p>True if the book was successfully copied</p>
      */
-    private boolean copyNextGenerationBook(BookMeta bookMeta, Player player, int copies) {
+    private boolean copyNextGenerationBook(@NotNull BookMeta bookMeta, @NotNull Player player, int copies) {
         //Copy the vanilla behavior of refusing copying any further
         if (bookMeta.getGeneration() == BookMeta.Generation.COPY_OF_COPY ||
                 bookMeta.getGeneration() == BookMeta.Generation.TATTERED) {
@@ -140,10 +141,10 @@ public class CommandCopy implements TabExecutor {
 
     @Override
     public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-                                      @NotNull String[] args) {
+                                      @NotNull String[] arguments) {
-        int argumentCount = args.length;
+        int argumentCount = arguments.length;
         if (argumentCount == 1) {
-            return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getNumbers(1, 20), args[0]);
+            return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getNumbers(1, 20), arguments[0]);
         }
         return new ArrayList<>();
     }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandDecrypt.java

@@ -99,8 +99,9 @@ public class CommandDecrypt implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-        int argumentCount = args.length;
+                                      @NotNull String[] arguments) {
+        int argumentCount = arguments.length;
         if (argumentCount == 1) {
             List<String> info = new ArrayList<>();
             info.add("<password>");

src/main/java/net/knarcraft/bookswithoutborders/command/CommandDelete.java

@@ -1,6 +1,7 @@
 package net.knarcraft.bookswithoutborders.command;
 
 import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import net.knarcraft.bookswithoutborders.gui.PagedBookIndex;
 import net.knarcraft.bookswithoutborders.state.BookDirectory;
 import net.knarcraft.bookswithoutborders.utility.BookFileHelper;
 import net.knarcraft.bookswithoutborders.utility.BookHelper;
@@ -21,34 +22,35 @@ import java.util.List;
 public class CommandDelete implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
         }
 
-        return deleteBook(sender, args, false);
+        return deleteBook(sender, arguments, false);
     }
 
     /**
      * Deletes a book
      *
      * @param sender       <p>The sender trying to delete the book</p>
-     * @param args         <p>The arguments given</p>
+     * @param arguments    <p>The arguments given</p>
      * @param deletePublic <p>Whether to delete a public book</p>
      * @return <p>True if the book was deleted successfully</p>
      */
-    boolean deleteBook(CommandSender sender, String[] args, boolean deletePublic) {
+    protected boolean deleteBook(@NotNull CommandSender sender, @NotNull String[] arguments, boolean deletePublic) {
-        //List deletable files
+        String command = deletePublic ? "deletepublicbook" : "deletebook";
-        if (args.length == 0) {
+        if (PagedBookIndex.displayPage(arguments, sender, deletePublic, command)) {
-            BookFileHelper.printBooks(sender, deletePublic);
             return true;
         }
+
         //Delete the file
-        if (args.length == 1) {
+        if (arguments.length == 1) {
             List<String> availableBooks = BooksWithoutBorders.getAvailableBooks(sender, deletePublic);
             if (!availableBooks.isEmpty()) {
-                performBookDeletion(sender, args[0], deletePublic);
+                performBookDeletion(sender, arguments[0], deletePublic);
                 //Update the book list
                 BooksWithoutBorders.updateBooks(sender, deletePublic);
                 return true;
@@ -68,7 +70,7 @@ public class CommandDelete implements TabExecutor {
      * @param fileName <p>The file name of the book</p>
      * @param isPublic <p>Whether the book to delete is public or not</p>
      */
-    public void performBookDeletion(CommandSender sender, String fileName, Boolean isPublic) {
+    public void performBookDeletion(@NotNull CommandSender sender, @NotNull String fileName, @NotNull Boolean isPublic) {
         //If the file name is an index of the load list, load the book
         try {
             int loadListIndex = Integer.parseInt(fileName);
@@ -103,8 +105,9 @@ public class CommandDelete implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-        return doTabCompletion(sender, args, false);
+                                      @NotNull String[] arguments) {
+        return doTabCompletion(sender, arguments, false);
     }
 
     /**
@@ -115,7 +118,8 @@ public class CommandDelete implements TabExecutor {
      * @param deletePublic <p>Whether to delete a public book</p>
      * @return <p>A list of available arguments</p>
      */
-    protected List<String> doTabCompletion(CommandSender sender, String[] args, boolean deletePublic) {
+    @NotNull
+    protected List<String> doTabCompletion(@NotNull CommandSender sender, @NotNull String[] args, boolean deletePublic) {
         int argumentCount = args.length;
         if (argumentCount == 1) {
             return TabCompletionHelper.filterMatchingContains(BooksWithoutBorders.getAvailableBooks(sender, deletePublic),

src/main/java/net/knarcraft/bookswithoutborders/command/CommandDeletePublic.java

@@ -13,13 +13,13 @@ import java.util.List;
 public class CommandDeletePublic extends CommandDelete implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] arguments) {
-        return deleteBook(sender, args, true);
+        return deleteBook(sender, arguments, true);
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] arguments) {
-        return doTabCompletion(sender, args, true);
+        return doTabCompletion(sender, arguments, true);
     }
 
 }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandEncrypt.java

@@ -13,6 +13,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -23,25 +24,28 @@ import java.util.List;
 public class CommandEncrypt implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-        if (performPreChecks(sender, args, 1, "You must specify a key to encrypt a book!") == null) {
+                             @NotNull String[] arguments) {
+        if (performPreChecks(sender, arguments, 1, "You must specify a key to encrypt a book!") == null) {
             return false;
         }
 
-        EncryptionStyle encryptionStyle = args.length == 2 ? EncryptionStyle.getFromString(args[1]) : EncryptionStyle.SUBSTITUTION;
+        EncryptionStyle encryptionStyle = arguments.length == 2 ? EncryptionStyle.getFromString(arguments[1]) : EncryptionStyle.SUBSTITUTION;
-        return encryptBook(encryptionStyle, (Player) sender, args[0], "");
+        return encryptBook(encryptionStyle, (Player) sender, arguments[0], "");
     }
 
     /**
      * Performs necessary pre-checks before going through with the encryption
      *
      * @param sender                <p>The sender trying to encrypt a book</p>
-     * @param args                  <p>The arguments given</p>
+     * @param arguments             <p>The arguments given</p>
      * @param necessaryArguments    <p>How many arguments is the minimum requirement</p>
      * @param missingArgumentsError <p>The error to show if a required argument is missing</p>
      * @return <p>The metadata of the book to encrypt, or null if any checks fail</p>
      */
-    BookMeta performPreChecks(CommandSender sender, String[] args, int necessaryArguments, String missingArgumentsError) {
+    @Nullable
+    protected BookMeta performPreChecks(@NotNull CommandSender sender, @NotNull String[] arguments,
+                                        int necessaryArguments, @NotNull String missingArgumentsError) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return null;
@@ -53,7 +57,7 @@ public class CommandEncrypt implements TabExecutor {
             return null;
         }
 
-        int argumentCount = args.length;
+        int argumentCount = arguments.length;
         if (argumentCount < necessaryArguments) {
             BooksWithoutBorders.sendErrorMessage(player, missingArgumentsError);
             return null;
@@ -85,7 +89,8 @@ public class CommandEncrypt implements TabExecutor {
      * @param group           <p>The group to encrypt for</p>
      * @return <p>True if the book was encrypted successfully</p>
      */
-    boolean encryptBook(EncryptionStyle encryptionStyle, Player player, String key, String group) {
+    protected boolean encryptBook(@NotNull EncryptionStyle encryptionStyle, @NotNull Player player, @NotNull String key,
+                                  @NotNull String group) {
         ItemSlot heldSlot = InventoryHelper.getHeldSlotBook(player, false, false, true, true);
         ItemStack encryptedBook = EncryptionHelper.encryptBook(player, heldSlot == ItemSlot.MAIN_HAND, key, encryptionStyle, group);
 
@@ -98,8 +103,10 @@ public class CommandEncrypt implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    @NotNull
-        return doTabCompletion(args, false);
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
+        return doTabCompletion(arguments, false);
     }
 
     /**
@@ -109,7 +116,8 @@ public class CommandEncrypt implements TabExecutor {
      * @param groupEncrypt <p>Whether to auto-complete for group encryption</p>
      * @return <p>The strings to auto-complete</p>
      */
-    protected List<String> doTabCompletion(String[] args, boolean groupEncrypt) {
+    @NotNull
+    protected List<String> doTabCompletion(@NotNull String[] args, boolean groupEncrypt) {
         int argumentsCount = args.length;
 
         List<String> encryptionStyles = new ArrayList<>();

src/main/java/net/knarcraft/bookswithoutborders/command/CommandFormat.java

@@ -20,7 +20,8 @@ import java.util.List;
 public class CommandFormat implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
@@ -32,7 +33,14 @@ public class CommandFormat implements TabExecutor {
         }
 
         ItemStack heldBook = InventoryHelper.getHeldBook(player, true);
-        heldBook.setItemMeta(BookFormatter.formatPages((BookMeta) heldBook.getItemMeta()));
+        BookMeta meta = (BookMeta) heldBook.getItemMeta();
+
+        if (meta == null) {
+            BooksWithoutBorders.sendErrorMessage(sender, "Unable to get metadata from the held book!");
+            return false;
+        }
+
+        heldBook.setItemMeta(BookFormatter.formatPages(meta));
 
         BooksWithoutBorders.sendSuccessMessage(sender, "Book formatted!");
 
@@ -40,7 +48,8 @@ public class CommandFormat implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
         return new ArrayList<>();
     }
 

src/main/java/net/knarcraft/bookswithoutborders/command/CommandGive.java

@@ -1,7 +1,7 @@
 package net.knarcraft.bookswithoutborders.command;
 
 import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
-import net.knarcraft.bookswithoutborders.utility.BookFileHelper;
+import net.knarcraft.bookswithoutborders.gui.PagedBookIndex;
 import net.knarcraft.bookswithoutborders.utility.BookLoader;
 import net.knarcraft.bookswithoutborders.utility.InputCleaningHelper;
 import net.knarcraft.bookswithoutborders.utility.TabCompletionTypeHelper;
@@ -13,6 +13,7 @@ import org.bukkit.command.TabExecutor;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -25,48 +26,50 @@ public class CommandGive implements TabExecutor {
     private final BooksWithoutBorders booksWithoutBorders = BooksWithoutBorders.getInstance();
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
         }
 
-        return giveBook(sender, args, false, "player");
+        return giveBook(sender, arguments, false, "player");
     }
 
     /**
      * Gives a book to another player
      *
      * @param sender     <p>The sender trying to give a book</p>
-     * @param args       <p>The arguments given</p>
+     * @param arguments  <p>The arguments given</p>
      * @param givePublic <p>Whether to give a public book</p>
      * @param folder     <p>The folder containing the book to load</p>
      * @return <p>True if the book was given successfully</p>
      */
-    boolean giveBook(CommandSender sender, String[] args, boolean givePublic, String folder) {
+    boolean giveBook(@NotNull CommandSender sender, @NotNull String[] arguments, boolean givePublic,
-        if (args.length == 1 || args.length > 4) {
+                     @NotNull String folder) {
+        String command = givePublic ? "givepublicbook" : "givebook";
+        if (PagedBookIndex.displayPage(arguments, sender, givePublic, command)) {
+            return true;
+        }
+
+        if (arguments.length == 1 || arguments.length > 4) {
             BooksWithoutBorders.sendErrorMessage(sender, "Incorrect number of arguments for this command!");
             return false;
         }
 
-        if (args.length == 0) {
-            BookFileHelper.printBooks(sender, givePublic);
-            return true;
-        }
-
         //Organize and parse input
-        String bookIdentifier = args[0];
+        String bookIdentifier = arguments[0];
-        String receivingPlayerName = args[1];
+        String receivingPlayerName = arguments[1];
         String copies = "1";
         String isSigned = "true";
-        if (args.length == 4) {
+        if (arguments.length == 4) {
-            copies = args[2];
+            copies = arguments[2];
-            isSigned = args[3];
+            isSigned = arguments[3];
-        } else if (args.length == 3) {
+        } else if (arguments.length == 3) {
-            if (args[2].equalsIgnoreCase("true") || args[2].equalsIgnoreCase("false")) {
+            if (arguments[2].equalsIgnoreCase("true") || arguments[2].equalsIgnoreCase("false")) {
-                isSigned = args[2];
+                isSigned = arguments[2];
             } else {
-                copies = args[2];
+                copies = arguments[2];
             }
         }
 
@@ -100,8 +103,9 @@ public class CommandGive implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-        return doTabCompletion(sender, args, false);
+                                      @NotNull String[] arguments) {
+        return doTabCompletion(sender, arguments, false);
     }
 
     /**
@@ -112,7 +116,8 @@ public class CommandGive implements TabExecutor {
      * @param listPublic <p>Whether to list public files or player files</p>
      * @return <p>A list of available choices</p>
      */
-    protected List<String> doTabCompletion(CommandSender sender, String[] args, boolean listPublic) {
+    @Nullable
+    protected List<String> doTabCompletion(@NotNull CommandSender sender, @NotNull String[] args, boolean listPublic) {
         Server server = booksWithoutBorders.getServer();
 
         int argumentCount = args.length;
@@ -157,8 +162,9 @@ public class CommandGive implements TabExecutor {
      * @param copies          <p>The number of copies the player wants to give</p>
      * @return <p>True if the book was successfully given</p>
      */
-    private boolean loadAndGiveBook(String bookIdentifier, CommandSender sender, Player receivingPlayer,
+    private boolean loadAndGiveBook(@NotNull String bookIdentifier, @NotNull CommandSender sender,
-                                    String isSigned, String folder, String copies) throws NumberFormatException {
+                                    @NotNull Player receivingPlayer, @NotNull String isSigned, @NotNull String folder,
+                                    @NotNull String copies) throws NumberFormatException {
         String bookToLoad = InputCleaningHelper.cleanString(bookIdentifier);
         ItemStack newBook = BookLoader.loadBook(sender, bookToLoad, isSigned, folder, Integer.parseInt(copies));
         if (newBook != null) {

src/main/java/net/knarcraft/bookswithoutborders/command/CommandGivePublic.java

@@ -4,6 +4,7 @@ import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
 import org.bukkit.command.TabExecutor;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.List;
 
@@ -13,13 +14,16 @@ import java.util.List;
 public class CommandGivePublic extends CommandGive implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-        return giveBook(sender, args, true, "public");
+                             @NotNull String[] arguments) {
+        return giveBook(sender, arguments, true, "public");
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    @Nullable
-        return doTabCompletion(sender, args, true);
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
+        return doTabCompletion(sender, arguments, true);
     }
 
 }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandGroupEncrypt.java

@@ -17,8 +17,9 @@ import java.util.List;
 public class CommandGroupEncrypt extends CommandEncrypt implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-        BookMeta bookMetadata = performPreChecks(sender, args, 2,
+                             @NotNull String[] arguments) {
+        BookMeta bookMetadata = performPreChecks(sender, arguments, 2,
                 "You must specify a group name and key to encrypt a book!");
 
         if (bookMetadata == null) {
@@ -32,13 +33,14 @@ public class CommandGroupEncrypt extends CommandEncrypt implements TabExecutor {
             return false;
         }
 
-        EncryptionStyle encryptionStyle = args.length == 3 ? EncryptionStyle.getFromString(args[2]) : EncryptionStyle.SUBSTITUTION;
+        EncryptionStyle encryptionStyle = arguments.length == 3 ? EncryptionStyle.getFromString(arguments[2]) : EncryptionStyle.SUBSTITUTION;
-        return encryptBook(encryptionStyle, (Player) sender, args[1], args[0]);
+        return encryptBook(encryptionStyle, (Player) sender, arguments[1], arguments[0]);
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    public @NotNull List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command,
-        return doTabCompletion(args, true);
+                                               @NotNull String alias, @NotNull String[] arguments) {
+        return doTabCompletion(arguments, true);
     }
 
 }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandLoad.java

@@ -1,7 +1,7 @@
 package net.knarcraft.bookswithoutborders.command;
 
 import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
-import net.knarcraft.bookswithoutborders.utility.BookFileHelper;
+import net.knarcraft.bookswithoutborders.gui.PagedBookIndex;
 import net.knarcraft.bookswithoutborders.utility.BookLoader;
 import net.knarcraft.bookswithoutborders.utility.InputCleaningHelper;
 import net.knarcraft.bookswithoutborders.utility.TabCompletionTypeHelper;
@@ -22,20 +22,22 @@ import java.util.List;
 public class CommandLoad implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-        return loadBook(sender, args, "player", false);
+                             @NotNull String[] arguments) {
+        return loadBook(sender, arguments, "player", false);
     }
 
     /**
      * Loads a stored book
      *
      * @param sender     <p>The sender asking to load the book</p>
-     * @param args       <p>The arguments given</p>
+     * @param arguments  <p>The arguments given</p>
      * @param directory  <p>The directory to load from (public/player)</p>
      * @param loadPublic <p>Whether to list public files as loadable</p>
      * @return <p>True if the book was loaded successfully</p>
      */
-    public boolean loadBook(CommandSender sender, String[] args, String directory, boolean loadPublic) {
+    public boolean loadBook(@NotNull CommandSender sender, @NotNull String[] arguments, @NotNull String directory,
+                            boolean loadPublic) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
@@ -46,26 +48,25 @@ public class CommandLoad implements TabExecutor {
             return false;
         }
 
-        int argumentCount = args.length;
+        int argumentCount = arguments.length;
 
-        //Show books available to the player
+        String command = loadPublic ? "loadpublicbook" : "loadbook";
-        if (argumentCount == 0) {
+        if (PagedBookIndex.displayPage(arguments, sender, loadPublic, command)) {
-            BookFileHelper.printBooks(sender, loadPublic);
             return true;
         }
 
         //Organize and parse input
-        String bookIdentifier = args[0];
+        String bookIdentifier = arguments[0];
         String copies = "1";
         String isSigned = "true";
-        if (args.length == 3) {
+        if (argumentCount == 3) {
-            copies = args[1];
+            copies = arguments[1];
-            isSigned = args[2];
+            isSigned = arguments[2];
-        } else if (args.length == 2) {
+        } else if (argumentCount == 2) {
-            if (args[1].equalsIgnoreCase("true") || args[1].equalsIgnoreCase("false")) {
+            if (arguments[1].equalsIgnoreCase("true") || arguments[1].equalsIgnoreCase("false")) {
-                isSigned = args[1];
+                isSigned = arguments[1];
             } else {
-                copies = args[1];
+                copies = arguments[1];
             }
         }
 
@@ -95,32 +96,34 @@ public class CommandLoad implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-        return doTabCompletion(sender, args, false);
+                                      @NotNull String[] arguments) {
+        return doTabCompletion(sender, arguments, false);
     }
 
     /**
      * Performs the actual tab completion
      *
      * @param sender     <p>The sender of the command</p>
-     * @param args       <p>The arguments given</p>
+     * @param arguments  <p>The arguments given</p>
      * @param loadPublic <p>Whether to list public files or player files</p>
      * @return <p>A list of available choices</p>
      */
-    protected List<String> doTabCompletion(CommandSender sender, String[] args, boolean loadPublic) {
+    @NotNull
-        int argumentCount = args.length;
+    protected List<String> doTabCompletion(@NotNull CommandSender sender, @NotNull String[] arguments, boolean loadPublic) {
+        int argumentCount = arguments.length;
         if (argumentCount == 1) {
             //Return list of books
             return TabCompletionHelper.filterMatchingContains(BooksWithoutBorders.getAvailableBooks(sender, loadPublic),
-                    args[0]);
+                    arguments[0]);
         } else if (argumentCount == 2) {
             //Number of copies
-            return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getBooleansAndNumbers(1, 3), args[1]);
+            return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getBooleansAndNumbers(1, 3), arguments[1]);
         } else if (argumentCount == 3) {
             //Signed
             try {
-                Integer.parseInt(args[1]);
+                Integer.parseInt(arguments[1]);
-                return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getBooleans(), args[2]);
+                return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getBooleans(), arguments[2]);
             } catch (NumberFormatException e) {
                 return new ArrayList<>();
             }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandLoadPublic.java

@@ -13,13 +13,15 @@ import java.util.List;
 public class CommandLoadPublic extends CommandLoad implements CommandExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-        return loadBook(sender, args, "public", true);
+                             @NotNull String[] arguments) {
+        return loadBook(sender, arguments, "public", true);
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-        return doTabCompletion(sender, args, true);
+                                      @NotNull String[] arguments) {
+        return doTabCompletion(sender, arguments, true);
     }
 
 }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandReload.java

@@ -16,18 +16,24 @@ import java.util.List;
 public class CommandReload implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (BooksWithoutBordersConfig.loadConfig()) {
             BooksWithoutBorders.sendSuccessMessage(sender, "BooksWithoutBorders configuration reloaded!");
         } else {
             BooksWithoutBorders.sendErrorMessage(sender, "Reload Failed!");
             BooksWithoutBorders.sendErrorMessage(sender, "See console for details");
         }
+
+        // Reload books
+        BooksWithoutBorders.updateBooks(sender, true);
+        BooksWithoutBorders.clearBookData();
         return true;
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
         return new ArrayList<>();
     }
 

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSave.java

@@ -8,6 +8,7 @@ import net.knarcraft.bookswithoutborders.utility.BookFileHelper;
 import net.knarcraft.bookswithoutborders.utility.BookHelper;
 import net.knarcraft.bookswithoutborders.utility.BookToFromTextHelper;
 import net.knarcraft.bookswithoutborders.utility.InventoryHelper;
+import net.md_5.bungee.api.ChatColor;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
 import org.bukkit.command.TabExecutor;
@@ -32,28 +33,28 @@ import static net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig
 public class CommandSave implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] arguments) {
-        return saveHeldBook(sender, args, false);
+        return saveHeldBook(sender, arguments, false);
     }
 
     /**
      * Saves the player's held book if it exists
      *
      * @param sender     <p>The sender of the command</p>
-     * @param args       <p>The arguments given</p>
+     * @param arguments  <p>The arguments given</p>
      * @param savePublic <p>Whether to save the book in the public directory or the player directory</p>
      * @return <p>True if a book was saved successfully</p>
      */
-    boolean saveHeldBook(CommandSender sender, String[] args, boolean savePublic) {
+    boolean saveHeldBook(@NotNull CommandSender sender, @NotNull String[] arguments, boolean savePublic) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
         }
 
         ItemSlot holdingSlot = InventoryHelper.getHeldSlotBook(player, false, false, false, false);
-        if (holdingSlot != null && holdingSlot != ItemSlot.NONE) {
+        if (holdingSlot != ItemSlot.NONE) {
             ItemStack holdingItem = InventoryHelper.getHeldItem(player, holdingSlot == ItemSlot.MAIN_HAND);
-            boolean duplicate = args.length == 1 && Boolean.parseBoolean(args[0]);
+            boolean duplicate = arguments.length == 1 && Boolean.parseBoolean(arguments[0]);
             saveBook(player, holdingItem, duplicate, savePublic);
             return true;
         } else {
@@ -70,7 +71,7 @@ public class CommandSave implements TabExecutor {
      * @param overwrite          <p>Whether to overwrite any existing books</p>
      * @param saveToPublicFolder <p>Whether to save the book to the public folder instead of the player folder</p>
      */
-    public void saveBook(Player player, ItemStack heldBook, boolean overwrite, boolean saveToPublicFolder) {
+    public void saveBook(@NotNull Player player, @NotNull ItemStack heldBook, boolean overwrite, boolean saveToPublicFolder) {
         BookMeta book = (BookMeta) heldBook.getItemMeta();
         if (book == null) {
             BooksWithoutBorders.sendErrorMessage(player, "Unable to get metadata for your held book!");
@@ -87,8 +88,19 @@ public class CommandSave implements TabExecutor {
         String savePath = BookHelper.getBookDirectoryPathString(
                 saveToPublicFolder ? BookDirectory.PUBLIC : BookDirectory.PLAYER, player);
 
+        if (savePath == null) {
+            BooksWithoutBorders.sendErrorMessage(player, "Saving Failed! Unable to find the save path!");
+            return;
+        }
+
         //Generate book filename
-        String fileName = BookHelper.getBookFile(book, player, saveToPublicFolder);
+        String fileName;
+        try {
+            fileName = BookHelper.getBookFile(book, player, saveToPublicFolder);
+        } catch (IllegalArgumentException exception) {
+            BooksWithoutBorders.sendErrorMessage(player, exception.getMessage());
+            return;
+        }
 
         //Make sure the used folders exist
         File file = new File(savePath);
@@ -142,7 +154,7 @@ public class CommandSave implements TabExecutor {
 
             //Update the relevant book list
             BooksWithoutBorders.updateBooks(player, saveToPublicFolder);
-            BooksWithoutBorders.sendSuccessMessage(player, "Book Saved as \"" + fileName + "\"");
+            BooksWithoutBorders.sendSuccessMessage(player, "Book Saved as \"" + fileName + ChatColor.RESET + "\"");
         } catch (IOException exception) {
             BooksWithoutBorders.getInstance().getLogger().log(Level.SEVERE, "Unable to save book");
         }
@@ -150,8 +162,9 @@ public class CommandSave implements TabExecutor {
     }
 
     @Override
+    @NotNull
     public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-                                      @NotNull String[] args) {
+                                      @NotNull String[] arguments) {
         return new ArrayList<>();
     }
 

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSavePublic.java

@@ -11,8 +11,9 @@ import org.jetbrains.annotations.NotNull;
 public class CommandSavePublic extends CommandSave implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-        return saveHeldBook(sender, args, true);
+                             @NotNull String[] arguments) {
+        return saveHeldBook(sender, arguments, true);
     }
 
 }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSetAuthor.java

@@ -12,6 +12,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -22,13 +23,14 @@ import java.util.List;
 public class CommandSetAuthor implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
         }
 
-        if (args.length < 1) {
+        if (arguments.length < 1) {
             BooksWithoutBorders.sendErrorMessage(player, "Too few command arguments!");
             return false;
         }
@@ -43,8 +45,12 @@ public class CommandSetAuthor implements TabExecutor {
         boolean mainHand = heldBookSlot == ItemSlot.MAIN_HAND;
         ItemStack heldBook = InventoryHelper.getHeldItem(player, mainHand);
         BookMeta bookMetaData = InventoryHelper.getHeldBookMetadata(player, mainHand);
+        if (bookMetaData == null) {
+            BooksWithoutBorders.sendErrorMessage(player, "Unable to get metadata for the held book!");
+            return false;
+        }
 
-        String author = ColorHelper.translateColorCodes(String.join(" ", args), ColorConversion.RGB);
+        String author = ColorHelper.translateColorCodes(String.join(" ", arguments), ColorConversion.RGB);
         bookMetaData.setAuthor(author);
         heldBook.setItemMeta(bookMetaData);
         BooksWithoutBorders.sendSuccessMessage(player, "Book author set to " + author + "!");
@@ -52,8 +58,10 @@ public class CommandSetAuthor implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    @Nullable
-        if (args.length == 1) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
+        if (arguments.length == 1) {
             return null;
         } else {
             return new ArrayList<>();

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSetBookPrice.java

@@ -26,35 +26,36 @@ public class CommandSetBookPrice implements TabExecutor {
     private List<String> paymentTypes;
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         //Clear the current price
-        if (args.length == 0) {
+        if (arguments.length == 0) {
             clearItemPrice(sender);
             return true;
         }
 
         //Warn about missing arguments
-        if (args.length < 2) {
+        if (arguments.length < 2) {
             BooksWithoutBorders.sendErrorMessage(sender, "[Item/Eco] and [quantity] must be specified!");
             return false;
         }
 
         //Warn about invalid argument
-        if (!args[0].equalsIgnoreCase("Item") && !args[0].equalsIgnoreCase("Eco")) {
+        if (!arguments[0].equalsIgnoreCase("Item") && !arguments[0].equalsIgnoreCase("Eco")) {
             BooksWithoutBorders.sendErrorMessage(sender, "Price type must be \"Item\" or \"Eco\"!");
             return false;
         }
 
         try {
-            double price = Double.parseDouble(args[1]);
+            double price = Double.parseDouble(arguments[1]);
             if (price <= 0) {
                 BooksWithoutBorders.sendErrorMessage(sender, "[quantity] must be greater than 0!");
                 return false;
             }
 
-            if (args[0].equalsIgnoreCase("Item")) {
+            if (arguments[0].equalsIgnoreCase("Item")) {
                 return setItemPrice(sender, price);
-            } else if (args[0].equalsIgnoreCase("Eco")) {
+            } else if (arguments[0].equalsIgnoreCase("Eco")) {
                 return setEconomyPrice(sender, price);
             }
         } catch (NumberFormatException e) {
@@ -68,7 +69,7 @@ public class CommandSetBookPrice implements TabExecutor {
      *
      * @param sender <p>The sender of the command</p>
      */
-    private void clearItemPrice(CommandSender sender) {
+    private void clearItemPrice(@NotNull CommandSender sender) {
         BooksWithoutBordersConfig.setBookPriceType(null);
         BooksWithoutBordersConfig.setBookPriceQuantity(0);
         booksWithoutBorders.getConfig().set("Options.Price_to_create_book.Item_type", "Item type name");
@@ -85,7 +86,7 @@ public class CommandSetBookPrice implements TabExecutor {
      * @param price  <p>The new price</p>
      * @return <p>True if the price was changed successfully</p>
      */
-    private boolean setItemPrice(CommandSender sender, double price) {
+    private boolean setItemPrice(@NotNull CommandSender sender, double price) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "[Item] price can only be used by a player!");
             return false;
@@ -117,7 +118,7 @@ public class CommandSetBookPrice implements TabExecutor {
      * @param price  <p>The new price</p>
      * @return <p>True if the price was changed successfully</p>
      */
-    private boolean setEconomyPrice(CommandSender sender, double price) {
+    private boolean setEconomyPrice(@NotNull CommandSender sender, double price) {
         if (EconomyHelper.setupEconomy()) {
             BooksWithoutBordersConfig.setBookPriceQuantity(price);
             BooksWithoutBordersConfig.setBookPriceType(Material.AIR);
@@ -136,16 +137,17 @@ public class CommandSetBookPrice implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
         if (paymentTypes == null) {
             initializeTabCompleteLists();
         }
 
-        int argumentCount = args.length;
+        int argumentCount = arguments.length;
         if (argumentCount == 1) {
-            return TabCompletionHelper.filterMatchingStartsWith(paymentTypes, args[0]);
+            return TabCompletionHelper.filterMatchingStartsWith(paymentTypes, arguments[0]);
         } else if (argumentCount == 2) {
-            return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getNumbers(1, 3), args[1]);
+            return TabCompletionHelper.filterMatchingStartsWith(TabCompletionTypeHelper.getNumbers(1, 3), arguments[1]);
         }
         return new ArrayList<>();
     }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSetBookshelfData.java

@@ -0,0 +1,111 @@
+package net.knarcraft.bookswithoutborders.command;
+
+import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig;
+import net.knarcraft.bookswithoutborders.container.Bookshelf;
+import net.knarcraft.bookswithoutborders.handler.BookshelfHandler;
+import net.knarcraft.knarlib.util.TabCompletionHelper;
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabExecutor;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * The command for setting information for a chiseled bookshelf
+ */
+public class CommandSetBookshelfData implements TabExecutor {
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
+                             @NotNull String[] arguments) {
+        if (!(commandSender instanceof Player player)) {
+            BooksWithoutBorders.sendErrorMessage(commandSender, "This command must be used by a player!");
+            return false;
+        }
+
+        Block targetBlock = player.getTargetBlockExact(7);
+        if (targetBlock == null || targetBlock.getType() != Material.CHISELED_BOOKSHELF) {
+            BooksWithoutBorders.sendErrorMessage(commandSender, "You are not looking at a bookshelf!");
+            return false;
+        }
+
+        BookshelfHandler shelfHandler = BooksWithoutBorders.getBookshelfHandler();
+        Bookshelf bookshelf = shelfHandler.getFromLocation(targetBlock.getLocation());
+
+        if (arguments.length < 2) {
+            if (arguments.length == 1 && arguments[0].equalsIgnoreCase("delete")) {
+                if (bookshelf != null) {
+                    shelfHandler.unregisterBookshelf(bookshelf);
+                    shelfHandler.save();
+                    BooksWithoutBorders.sendSuccessMessage(commandSender, "Bookshelf successfully deleted");
+                } else {
+                    BooksWithoutBorders.sendErrorMessage(commandSender, "The block you are looking at is not a registered bookshelf");
+                }
+                return true;
+            } else {
+                return false;
+            }
+        }
+
+        // Get all arguments as a space-separated string
+        StringBuilder builder = new StringBuilder(arguments[1]);
+        for (int i = 2; i < arguments.length; i++) {
+            builder.append(" ").append(arguments[i]);
+        }
+
+        switch (arguments[0].toLowerCase()) {
+            case "name":
+                if (bookshelf == null) {
+                    Bookshelf newShelf = new Bookshelf(targetBlock.getLocation(), arguments[1], new ArrayList<>());
+                    shelfHandler.registerBookshelf(newShelf);
+                } else {
+                    bookshelf.setTitle(builder.toString());
+                }
+                shelfHandler.save();
+                BooksWithoutBorders.sendSuccessMessage(commandSender, "Title successfully saved");
+                return true;
+            case "lore":
+                if (bookshelf == null) {
+                    BooksWithoutBorders.sendErrorMessage(commandSender, "You must name the bookshelf before " +
+                            "assigning lore!");
+                } else {
+                    List<String> loreParts = Arrays.asList(builder.toString().split(BooksWithoutBordersConfig.getLoreSeparator()));
+                    bookshelf.setLore(loreParts);
+                    shelfHandler.save();
+                    BooksWithoutBorders.sendSuccessMessage(commandSender, "Lore successfully saved");
+                }
+                return true;
+        }
+
+        return false;
+    }
+
+    @Nullable
+    @Override
+    public List<String> onTabComplete(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
+                                      @NotNull String[] arguments) {
+        if (arguments.length == 1) {
+            return TabCompletionHelper.filterMatchingStartsWith(List.of("delete", "name", "lore"), arguments[0]);
+        } else if (arguments.length == 2) {
+            return switch (arguments[0].toLowerCase()) {
+                case "delete" -> new ArrayList<>();
+                case "name" ->
+                        TabCompletionHelper.filterMatchingStartsWith(List.of("Epic Title", "Lame Title"), arguments[1]);
+                case "lore" ->
+                        TabCompletionHelper.filterMatchingStartsWith(List.of("Interesting lore", "Line1~Line2~Line3"), arguments[1]);
+                default -> null;
+            };
+        } else {
+            return List.of();
+        }
+    }
+
+}

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSetGeneration.java

@@ -21,7 +21,7 @@ public class CommandSetGeneration implements TabExecutor {
 
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-                             @NotNull String[] args) {
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
@@ -32,14 +32,14 @@ public class CommandSetGeneration implements TabExecutor {
             return false;
         }
 
-        if (args.length < 1) {
+        if (arguments.length < 1) {
             BooksWithoutBorders.sendErrorMessage(player, "You must specify the new generation for your book!");
             return false;
         }
 
         BookMeta.Generation generation;
         try {
-            generation = BookMeta.Generation.valueOf(args[0]);
+            generation = BookMeta.Generation.valueOf(arguments[0]);
         } catch (IllegalArgumentException exception) {
             BooksWithoutBorders.sendErrorMessage(player, "Invalid book generation specified!");
             return false;
@@ -60,8 +60,8 @@ public class CommandSetGeneration implements TabExecutor {
     @Nullable
     @Override
     public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-                                      @NotNull String[] args) {
+                                      @NotNull String[] arguments) {
-        if (args.length == 1) {
+        if (arguments.length == 1) {
             List<String> generations = new ArrayList<>();
             for (BookMeta.Generation generation : BookMeta.Generation.values()) {
                 generations.add(generation.name());

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSetLore.java

@@ -24,13 +24,14 @@ import java.util.List;
 public class CommandSetLore implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
         }
 
-        if (args.length < 1) {
+        if (arguments.length < 1) {
             BooksWithoutBorders.sendErrorMessage(player, "Missing a command argument!");
             return false;
         }
@@ -42,12 +43,11 @@ public class CommandSetLore implements TabExecutor {
         }
 
         //Treat all arguments as lore input
-        String rawLore = String.join(" ", args);
+        String rawLore = String.join(" ", arguments);
 
         //Format lore
         rawLore = ColorHelper.translateColorCodes(rawLore, ColorConversion.RGB);
-        String[] loreParts = rawLore.split(BooksWithoutBordersConfig.getLoreSeparator());
+        List<String> newLore = Arrays.asList(rawLore.split(BooksWithoutBordersConfig.getLoreSeparator()));
-        List<String> newLore = new ArrayList<>(Arrays.asList(loreParts));
 
         //Update lore
         ItemMeta meta = heldItem.getItemMeta();
@@ -62,7 +62,8 @@ public class CommandSetLore implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, String[] args) {
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
         //TODO: Figure out if there is a better way to display that an argument is required
         List<String> options = new ArrayList<>();
         options.add("<new lore>");

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSetTitle.java

@@ -24,13 +24,13 @@ public class CommandSetTitle implements TabExecutor {
 
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
-                             @NotNull String[] args) {
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
         }
 
-        if (args.length < 1) {
+        if (arguments.length < 1) {
             BooksWithoutBorders.sendErrorMessage(player, "Too few command arguments!");
             return false;
         }
@@ -41,7 +41,7 @@ public class CommandSetTitle implements TabExecutor {
             return false;
         }
 
-        String title = String.join(" ", args);
+        String title = String.join(" ", arguments);
         title = ColorHelper.translateColorCodes(title, ColorConversion.RGB);
 
         ItemMeta itemMetadata = heldItem.getItemMeta();
@@ -69,7 +69,7 @@ public class CommandSetTitle implements TabExecutor {
 
     @Override
     public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
-                                      @NotNull String[] args) {
+                                      @NotNull String[] arguments) {
         List<String> options = new ArrayList<>();
         options.add("<new title>");
         return options;

src/main/java/net/knarcraft/bookswithoutborders/command/CommandUnSign.java

@@ -26,7 +26,8 @@ import java.util.logging.Level;
 public class CommandUnSign implements TabExecutor {
 
     @Override
-    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] arguments) {
         if (!(sender instanceof Player player)) {
             BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
             return false;
@@ -49,9 +50,13 @@ public class CommandUnSign implements TabExecutor {
      * @param player   <p>The player holding the book</p>
      * @param mainHand <p>Whether the player is holding the book in its main hand or its off hand</p>
      */
-    public void unSignHeldBook(Player player, boolean mainHand) {
+    public void unSignHeldBook(@NotNull Player player, boolean mainHand) {
         //Get the old book
         BookMeta oldMetadata = InventoryHelper.getHeldBookMetadata(player, mainHand);
+        if (oldMetadata == null) {
+            BooksWithoutBorders.sendErrorMessage(player, "Unable to get metadata from the held book!");
+            return;
+        }
         ItemStack heldBook = InventoryHelper.getHeldBook(player, mainHand);
 
         //Only allow the owner to un-sign the book
@@ -85,7 +90,9 @@ public class CommandUnSign implements TabExecutor {
     }
 
     @Override
-    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias, @NotNull String[] args) {
+    @NotNull
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String alias,
+                                      @NotNull String[] arguments) {
         return new ArrayList<>();
     }
 

src/main/java/net/knarcraft/bookswithoutborders/config/BooksWithoutBordersConfig.java

@@ -6,6 +6,7 @@ import net.md_5.bungee.api.ChatColor;
 import org.bukkit.Material;
 import org.bukkit.command.ConsoleCommandSender;
 import org.bukkit.configuration.Configuration;
+import org.jetbrains.annotations.NotNull;
 
 import java.nio.file.FileSystems;
 import java.util.ArrayList;
@@ -48,7 +49,7 @@ public class BooksWithoutBordersConfig {
      *
      * @param booksWithoutBorders <p>The books without borders object used for getting required data</p>
      */
-    public static void initialize(BooksWithoutBorders booksWithoutBorders) {
+    public static void initialize(@NotNull BooksWithoutBorders booksWithoutBorders) {
         if (isInitialized) {
             throw new IllegalArgumentException("Settings class initialized twice. This should not happen!");
         }
@@ -388,7 +389,7 @@ public class BooksWithoutBordersConfig {
      * @param configOption <p>The configuration option to get the value for</p>
      * @return <p>The value of the option</p>
      */
-    private static String getString(Configuration config, ConfigOption configOption) {
+    private static String getString(@NotNull Configuration config, @NotNull ConfigOption configOption) {
         return config.getString(configOption.getConfigNode(), (String) configOption.getDefaultValue());
     }
 
@@ -399,7 +400,7 @@ public class BooksWithoutBordersConfig {
      * @param configOption <p>The configuration option to get the value for</p>
      * @return <p>The value of the option</p>
      */
-    private static boolean getBoolean(Configuration config, ConfigOption configOption) {
+    private static boolean getBoolean(@NotNull Configuration config, @NotNull ConfigOption configOption) {
         return config.getBoolean(configOption.getConfigNode(), (Boolean) configOption.getDefaultValue());
     }
 

src/main/java/net/knarcraft/bookswithoutborders/config/ConfigOption.java

@@ -1,5 +1,7 @@
 package net.knarcraft.bookswithoutborders.config;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * A representation of the different available config options
  */
@@ -90,7 +92,7 @@ public enum ConfigOption {
      * @param configNode   <p>The config node in the config file this option represents</p>
      * @param defaultValue <p>The default value for this config option</p>
      */
-    ConfigOption(String configNode, Object defaultValue) {
+    ConfigOption(@NotNull String configNode, @NotNull Object defaultValue) {
         this.configNode = configNode;
         this.defaultValue = defaultValue;
     }

src/main/java/net/knarcraft/bookswithoutborders/container/Bookshelf.java

@@ -0,0 +1,81 @@
+package net.knarcraft.bookswithoutborders.container;
+
+import org.bukkit.Location;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+/**
+ * A representation of a bookshelf with extra data used when displaying its contents
+ */
+public class Bookshelf {
+
+    private final @NotNull Location location;
+    private @NotNull String title;
+    private @NotNull List<String> lore;
+
+    /**
+     * Instantiates a new bookshelf
+     *
+     * @param location <p>The location of the bookshelf</p>
+     * @param title    <p>The title of the bookshelf</p>
+     * @param lore     <p>The lore of the bookshelf</p>
+     */
+    public Bookshelf(@NotNull Location location, @NotNull String title, @NotNull List<String> lore) {
+        this.location = location;
+        this.title = title;
+        this.lore = lore;
+    }
+
+    /**
+     * Gets the location of this bookshelf
+     *
+     * @return <p>The location of this bookshelf</p>
+     */
+    @NotNull
+    public Location getLocation() {
+        return this.location;
+    }
+
+    /**
+     * Gets the title of this bookshelf
+     *
+     * @return <p>The title of this bookshelf</p>
+     */
+    @NotNull
+    public String getTitle() {
+        return this.title;
+    }
+
+    /**
+     * Gets the lore of this bookshelf
+     *
+     * @return <p>The lore of this bookshelf</p>
+     */
+    @NotNull
+    public List<String> getLore() {
+        return this.lore;
+    }
+
+    /**
+     * Sets the title of this bookshelf
+     *
+     * @param title <p>The new title</p>
+     */
+    public void setTitle(@NotNull String title) {
+        if (title.isBlank()) {
+            throw new IllegalArgumentException("Bookshelves cannot have empty titles!");
+        }
+        this.title = title;
+    }
+
+    /**
+     * Sets the lore of this bookshelf
+     *
+     * @param lore <p>The new lore</p>
+     */
+    public void setLore(@NotNull List<String> lore) {
+        this.lore = lore;
+    }
+
+}

src/main/java/net/knarcraft/bookswithoutborders/encryption/AES.java

@@ -1,6 +1,8 @@
 package net.knarcraft.bookswithoutborders.encryption;
 
 import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
@@ -52,7 +54,8 @@ public class AES {
      * @param encrypt  <p>Whether to encrypt or decrypt the input</p>
      * @return <p>The encrypted/decrypted input, or null if anything went wrong</p>
      */
-    public String encryptDecryptText(String input, String password, boolean encrypt) {
+    @Nullable
+    public String encryptDecryptText(@NotNull String input, @NotNull String password, boolean encrypt) {
         //Make a key from the password
         SecretKeySpec secretKeySpec = getKeyFromPassword(password);
         //Get cipher instance
@@ -102,7 +105,7 @@ public class AES {
      * @param encryption <p>Whether the input should be encrypted or decrypted</p>
      * @return <p>The input in byte format</p>
      */
-    private byte[] getInputBytes(String input, boolean encryption) {
+    private byte[] getInputBytes(@NotNull String input, boolean encryption) {
         if (encryption) {
             return input.getBytes();
         } else {
@@ -117,6 +120,7 @@ public class AES {
      * @param encryption <p>Whether the output came from encryption or decryption</p>
      * @return <p>The output as a string</p>
      */
+    @NotNull
     private String createResult(byte[] output, boolean encryption) {
         if (encryption) {
             return Base64.getEncoder().encodeToString(output);
@@ -130,6 +134,7 @@ public class AES {
      *
      * @return <p>An AES cipher instance, or null if something went wrong</p>
      */
+    @Nullable
     private Cipher getAESCipher() {
         Cipher aes;
         try {
@@ -147,7 +152,8 @@ public class AES {
      * @param password <p>A user supplied password</p>
      * @return <p>A secret key spec or null if something went wrong</p>
      */
-    private SecretKeySpec getKeyFromPassword(String password) {
+    @Nullable
+    private SecretKeySpec getKeyFromPassword(@NotNull String password) {
         PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), this.passwordSalt, 1000, 128);
         SecretKeyFactory keyFactory;
         try {

src/main/java/net/knarcraft/bookswithoutborders/encryption/GenenCrypt.java

@@ -1,5 +1,7 @@
 package net.knarcraft.bookswithoutborders.encryption;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Random;
@@ -24,7 +26,7 @@ public class GenenCrypt {
      *
      * @param key <p>The key used to generate the codon table</p>
      */
-    public GenenCrypt(String key) {
+    public GenenCrypt(@NotNull String key) {
 
         // define the initial, unshuffled codon list of 4 base codons
         ArrayList<String> originalCodonList = new ArrayList<>();
@@ -114,7 +116,8 @@ public class GenenCrypt {
      * @param input <p>The input to encrypt</p>
      * @return <p>The encrypted input</p>
      */
-    public String encrypt(String input) {
+    @NotNull
+    public String encrypt(@NotNull String input) {
         StringBuilder output = new StringBuilder();
         for (int i = 0; i < input.length(); i++) {
             // insert junk bases
@@ -147,7 +150,8 @@ public class GenenCrypt {
      * @param input <p>The input to decrypt</p>
      * @return <p>The decrypted input</p>
      */
-    public String decrypt(String input) {
+    @NotNull
+    public String decrypt(@NotNull String input) {
         StringBuilder output = new StringBuilder();
         int keyCount = 0;
         int junk = key.charAt(0);

src/main/java/net/knarcraft/bookswithoutborders/encryption/SubstitutionCipher.java

@@ -1,5 +1,7 @@
 package net.knarcraft.bookswithoutborders.encryption;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.math.BigInteger;
 import java.util.StringTokenizer;
 
@@ -17,9 +19,10 @@ public class SubstitutionCipher {
     // using a string for the key, it is converted
     // a series of offsets that each character in the
     // original message is offset by
-    public String encrypt(String in, String key) {
+    @NotNull
+    public String encrypt(@NotNull String in, @NotNull String key) {
         StringBuilder output = new StringBuilder();
-        if (key != null && !key.isEmpty()) {
+        if (!key.isEmpty()) {
             StringTokenizer tokenizer = new StringTokenizer(key, ", "); // tokenizes the key
             // converts each number in the key to an integer and adds to an array
             int[] offsetArray = new int[tokenizer.countTokens()];
@@ -53,9 +56,10 @@ public class SubstitutionCipher {
     // method with a flag for encryption / decryption, but
     // I'm lazy.
     @SuppressWarnings("unused")
-    public String decrypt(String in, String key) {
+    @NotNull
+    public String decrypt(@NotNull String in, @NotNull String key) {
         StringBuilder output = new StringBuilder();
-        if (key != null && !key.isEmpty()) {
+        if (!key.isEmpty()) {
             StringTokenizer tokenizer = new StringTokenizer(key, ", "); // tokenizes the key
             // converts each number in the key to an integer and adds to an array
             int[] offsetArray = new int[tokenizer.countTokens()];
@@ -81,7 +85,8 @@ public class SubstitutionCipher {
     // encryption works just like decryption, but is
     // vulnerable if the same key is used more than once.
     @SuppressWarnings("unused")
-    public String oneTimePad(String in, String key) {
+    @NotNull
+    public String oneTimePad(@NotNull String in, @NotNull String key) {
         StringBuilder output = new StringBuilder();
         for (int i = 0; i < in.length(); i++) {
             output.append((char) (in.charAt(i) ^ key.charAt(i % key.length())));

src/main/java/net/knarcraft/bookswithoutborders/gui/AuthorBookIndex.java

@@ -0,0 +1,87 @@
+package net.knarcraft.bookswithoutborders.gui;
+
+import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import net.knarcraft.bookswithoutborders.utility.BookFormatter;
+import net.md_5.bungee.api.ChatColor;
+import net.md_5.bungee.api.chat.ClickEvent;
+import net.md_5.bungee.api.chat.ComponentBuilder;
+import net.md_5.bungee.api.chat.HoverEvent;
+import net.md_5.bungee.api.chat.hover.content.Text;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+public class AuthorBookIndex extends BookIndex {
+
+    private final static int booksPerPage = 10;
+
+    /**
+     * Prints the available books
+     *
+     * @param sender     <p>The sender to display the books to</p>
+     * @param listPublic <p>Whether to display public books</p>
+     * @param command    <p>The base command causing this to be called</p>
+     * @param page       <p>The page of the book list to display</p>
+     */
+    public static void printBooks(@NotNull CommandSender sender, boolean listPublic, @NotNull String command, int page,
+                                  @NotNull String authorName) {
+        List<String> availableBooks = BooksWithoutBorders.getAvailableBooks(sender, listPublic);
+        availableBooks.removeIf((bookPath) -> !BookFormatter.stripColor(bookPath.substring(0, bookPath.length() - 4).split(",")[1]).equalsIgnoreCase(authorName));
+
+        int totalPages = (int) Math.ceil((double) availableBooks.size() / booksPerPage);
+        if (page > totalPages) {
+            sender.sendMessage(ChatColor.GRAY + "No such page");
+        } else {
+            showAuthorBooks(sender, command, page, totalPages, availableBooks, authorName);
+        }
+    }
+
+    /**
+     * Shows a menu listing available books from an author
+     *
+     * @param sender         <p>The sender wanting to see the book menu</p>
+     * @param command        <p>The main command used to trigger display of the book menu</p>
+     * @param page           <p>The currently selected page</p>
+     * @param totalPages     <p>The total amount of pages</p>
+     * @param availableBooks <p>All books available to the sender</p>
+     * @param authorName     <p>The name of the author currently shown</p>
+     */
+    private static void showAuthorBooks(@NotNull CommandSender sender, @NotNull String command, int page,
+                                        int totalPages, @NotNull List<String> availableBooks, @NotNull String authorName) {
+        ComponentBuilder componentBuilder = new ComponentBuilder();
+
+        // Display the list of books, with the next and previous buttons
+        displayPreviousButton(componentBuilder, command + " author" + authorName, page);
+        componentBuilder.append("\n");
+        displayBookList(componentBuilder, command, page, availableBooks);
+        displayNextButton(componentBuilder, command + " author" + authorName, page, totalPages);
+
+        // Display total pages and the manual change page command suggestion
+        componentBuilder.append("   ", ComponentBuilder.FormatRetention.NONE);
+        displayTotalPages(componentBuilder, page, totalPages);
+        componentBuilder.append("   ", ComponentBuilder.FormatRetention.NONE);
+        sender.spigot().sendMessage(componentBuilder.create());
+    }
+
+    /**
+     * Displays the list of books on the current page
+     *
+     * @param componentBuilder <p>The component builder to append to</p>
+     * @param command          <p>The command used for switching pages</p>
+     * @param page             <p>The current page</p>
+     * @param availableBooks   <p>All available books</p>
+     */
+    protected static void displayBookList(@NotNull ComponentBuilder componentBuilder, @NotNull String command, int page,
+                                          @NotNull List<String> availableBooks) {
+        int startIndex = (page - 1) * booksPerPage;
+        for (int bookIndex = startIndex; bookIndex < Math.min(startIndex + booksPerPage, availableBooks.size()); bookIndex++) {
+            componentBuilder.append(getNiceName(availableBooks.get(bookIndex))).color(ChatColor.WHITE).event(
+                    new ClickEvent(ClickEvent.Action.SUGGEST_COMMAND, "/" + command + " " +
+                            availableBooks.get(bookIndex))).event(
+                    new HoverEvent(HoverEvent.Action.SHOW_TEXT, new Text("Select book by path")));
+            componentBuilder.append("\n");
+        }
+    }
+
+}

src/main/java/net/knarcraft/bookswithoutborders/gui/BookIndex.java

@@ -0,0 +1,163 @@
+package net.knarcraft.bookswithoutborders.gui;
+
+import net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig;
+import net.knarcraft.bookswithoutborders.utility.InputCleaningHelper;
+import net.md_5.bungee.api.ChatColor;
+import net.md_5.bungee.api.chat.ClickEvent;
+import net.md_5.bungee.api.chat.ComponentBuilder;
+import net.md_5.bungee.api.chat.HoverEvent;
+import net.md_5.bungee.api.chat.hover.content.Text;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Map;
+
+public abstract class BookIndex {
+
+    protected final static int booksPerPage = 10;
+    protected final static @NotNull ChatColor interactColor = ChatColor.of("#FFD700");
+    protected final static @NotNull ChatColor inactiveColor = ChatColor.of("#999999");
+
+    /**
+     * Displays the correct GUI, if specified in the given arguments
+     *
+     * @param arguments    <p>The arguments given by a command sender</p>
+     * @param sender       <p>The sender executing the command</p>
+     * @param selectPublic <p>Whether to display public books, or only those available to the command sender</p>
+     * @param command      <p>The command used for changing pages and making the final selection</p>
+     * @return <p>True if the GUI was displayed</p>
+     */
+    public static boolean displayPage(@NotNull String[] arguments, @NotNull CommandSender sender, boolean selectPublic,
+                                      @NotNull String command) {
+        if (arguments.length == 0) {
+            PagedBookIndex.printBooks(sender, selectPublic, command, 1);
+            return true;
+        } else if (arguments.length == 1) {
+            int page = InputCleaningHelper.parsePageNumber(arguments[0]);
+            if (page > 0) {
+                PagedBookIndex.printBooks(sender, selectPublic, command, page);
+                return true;
+            }
+        } else if (arguments.length == 2) {
+            String author = InputCleaningHelper.parseAuthorSpecifier(arguments[0]);
+            if (author != null) {
+                int page = InputCleaningHelper.parsePageNumber(arguments[1]);
+                if (page > 0) {
+                    AuthorBookIndex.printBooks(sender, selectPublic, command, page, author);
+                }
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Displays the suggestion for manually going to any page
+     *
+     * @param componentBuilder <p>The component builder to append to</p>
+     * @param command          <p>The command used for switching pages</p>
+     * @param page             <p>The current page</p>
+     */
+    protected static void displayPageCommand(@NotNull ComponentBuilder componentBuilder, @NotNull String command, int page) {
+        componentBuilder.append("[Page Command]", ComponentBuilder.FormatRetention.NONE).color(interactColor).event(new HoverEvent(
+                HoverEvent.Action.SHOW_TEXT, new Text("/" + command + " page" + page))).event(
+                new ClickEvent(ClickEvent.Action.SUGGEST_COMMAND, "/" + command + " page" + page));
+    }
+
+    /**
+     * Displays the current page and total amount of pages
+     *
+     * @param componentBuilder <p>The component builder to append to</p>
+     * @param page             <p>The current page</p>
+     * @param totalPages       <p>The total amount of pages</p>
+     */
+    protected static void displayTotalPages(@NotNull ComponentBuilder componentBuilder, int page, int totalPages) {
+        componentBuilder.append("Page " + page + " of " + totalPages,
+                ComponentBuilder.FormatRetention.NONE).color(inactiveColor);
+    }
+
+    /**
+     * Displays the alphabet-based page index
+     *
+     * @param componentBuilder <p>The component builder to append to</p>
+     * @param command          <p>The command used for switching pages</p>
+     * @param firstInstances   <p>The map of where the first index of a letter is found</p>
+     */
+    protected static void displayAlphabetIndex(@NotNull ComponentBuilder componentBuilder,
+                                               @NotNull String command, @NotNull Map<Character, Integer> firstInstances) {
+        componentBuilder.append("[index] <", ComponentBuilder.FormatRetention.NONE).color(inactiveColor);
+        for (int characterIndex = 0; characterIndex <= 25; characterIndex++) {
+            char character = (char) ('a' + characterIndex);
+            if (firstInstances.containsKey(character)) {
+                int pageIndex = (firstInstances.get(character) / booksPerPage) + 1;
+                componentBuilder.append(character + "").color(interactColor).event(
+                        new ClickEvent(ClickEvent.Action.RUN_COMMAND,
+                                "/" + command + " page" + pageIndex)).event(new HoverEvent(
+                        HoverEvent.Action.SHOW_TEXT, new Text("Books starting with " + character)));
+            } else {
+                componentBuilder.append(character + "", ComponentBuilder.FormatRetention.NONE).color(inactiveColor);
+            }
+        }
+        componentBuilder.append(">", ComponentBuilder.FormatRetention.NONE).color(inactiveColor);
+    }
+
+    /**
+     * Displays the previous page button
+     *
+     * @param componentBuilder <p>The component builder to append to</p>
+     * @param command          <p>The command used for switching pages</p>
+     * @param page             <p>The current page</p>
+     */
+    protected static void displayPreviousButton(@NotNull ComponentBuilder componentBuilder,
+                                                @NotNull String command, int page) {
+        if (page > 1) {
+            String fullCommand = "/" + command + " page" + (page - 1);
+            HoverEvent prevPagePreview = new HoverEvent(HoverEvent.Action.SHOW_TEXT, new Text("To page " + (page - 1)));
+            ClickEvent prevPageClick = new ClickEvent(ClickEvent.Action.RUN_COMMAND, fullCommand);
+            componentBuilder.append("Previous [<]", ComponentBuilder.FormatRetention.NONE).color(interactColor)
+                    .event(prevPagePreview).event(prevPageClick);
+        } else {
+            componentBuilder.append("Previous [<]", ComponentBuilder.FormatRetention.NONE).color(inactiveColor);
+        }
+    }
+
+    /**
+     * Displays the next page button
+     *
+     * @param componentBuilder <p>The component builder to append to</p>
+     * @param command          <p>The command used for switching pages</p>
+     * @param page             <p>The current page</p>
+     * @param totalPages       <p>The total amount of pages</p>
+     */
+    protected static void displayNextButton(@NotNull ComponentBuilder componentBuilder,
+                                            @NotNull String command, int page, int totalPages) {
+        if (page < totalPages) {
+            String fullCommand = "/" + command + " page" + (page + 1);
+            HoverEvent nextPagePreview = new HoverEvent(HoverEvent.Action.SHOW_TEXT, new Text("To page " + (page + 1)));
+            ClickEvent nextPageClick = new ClickEvent(ClickEvent.Action.RUN_COMMAND, fullCommand);
+            componentBuilder.append("Next [>]", ComponentBuilder.FormatRetention.NONE).color(interactColor)
+                    .event(nextPagePreview).event(nextPageClick);
+        } else {
+            componentBuilder.append("Next [>]", ComponentBuilder.FormatRetention.NONE).color(inactiveColor);
+        }
+    }
+
+    /**
+     * Gets a nice name from a book's path
+     *
+     * @param bookPath <p>The path of a book</p>
+     * @return <p>The prettified book name</p>
+     */
+    @NotNull
+    protected static String getNiceName(@NotNull String bookPath) {
+        String separator = BooksWithoutBordersConfig.getTitleAuthorSeparator();
+        bookPath = ChatColor.translateAlternateColorCodes('&', bookPath.substring(0, bookPath.length() - 4));
+        if (bookPath.contains(separator)) {
+            String[] parts = bookPath.split(separator);
+            return parts[0].replace("_", " ") + ChatColor.RESET + " by " + parts[1] + ChatColor.RESET;
+        } else {
+            return bookPath + ChatColor.RESET + " by Unknown" + ChatColor.RESET;
+        }
+    }
+
+}

src/main/java/net/knarcraft/bookswithoutborders/gui/PagedBookIndex.java

@@ -0,0 +1,118 @@
+package net.knarcraft.bookswithoutborders.gui;
+
+import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import net.knarcraft.bookswithoutborders.utility.BookFormatter;
+import net.md_5.bungee.api.ChatColor;
+import net.md_5.bungee.api.chat.ClickEvent;
+import net.md_5.bungee.api.chat.ComponentBuilder;
+import net.md_5.bungee.api.chat.HoverEvent;
+import net.md_5.bungee.api.chat.hover.content.Text;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A class for displaying a paged index of all available books
+ */
+public class PagedBookIndex extends BookIndex {
+
+    /**
+     * Prints the available books
+     *
+     * @param sender     <p>The sender to display the books to</p>
+     * @param listPublic <p>Whether to display public books</p>
+     * @param command    <p>The base command causing this to be called</p>
+     * @param page       <p>The page of the book list to display</p>
+     */
+    public static void printBooks(@NotNull CommandSender sender, boolean listPublic, @NotNull String command, int page) {
+        List<String> availableBooks = BooksWithoutBorders.getAvailableBooks(sender, listPublic);
+
+        Map<Character, Integer> firstInstances;
+        if (listPublic) {
+            firstInstances = BooksWithoutBorders.getLetterIndex(null);
+        } else if (sender instanceof Player player) {
+            firstInstances = BooksWithoutBorders.getLetterIndex(player.getUniqueId());
+        } else {
+            firstInstances = new HashMap<>();
+        }
+
+        int totalPages = (int) Math.ceil((double) availableBooks.size() / booksPerPage);
+        if (page > totalPages) {
+            sender.sendMessage(ChatColor.GRAY + "No such page");
+        } else {
+            showBookMenu(sender, command, page, totalPages, availableBooks, firstInstances);
+        }
+    }
+
+    /**
+     * Shows a menu listing available books
+     *
+     * @param sender         <p>The sender wanting to see the book menu</p>
+     * @param command        <p>The main command used to trigger display of the book menu</p>
+     * @param page           <p>The currently selected page</p>
+     * @param totalPages     <p>The total amount of pages</p>
+     * @param availableBooks <p>All books available to the sender</p>
+     * @param firstInstances <p>The map between a character, and the index of the first instance of that character in the book list</p>
+     */
+    private static void showBookMenu(@NotNull CommandSender sender, @NotNull String command, int page,
+                                     int totalPages, @NotNull List<String> availableBooks,
+                                     @NotNull Map<Character, Integer> firstInstances) {
+        ComponentBuilder componentBuilder = new ComponentBuilder();
+
+        // Display the list of books, with the next and previous buttons
+        displayPreviousButton(componentBuilder, command, page);
+        componentBuilder.append("\n");
+        displayBookList(componentBuilder, command, page, availableBooks);
+        displayNextButton(componentBuilder, command, page, totalPages);
+
+        // Display total pages and the manual change page command suggestion
+        componentBuilder.append("   ", ComponentBuilder.FormatRetention.NONE);
+        displayTotalPages(componentBuilder, page, totalPages);
+        componentBuilder.append("   ", ComponentBuilder.FormatRetention.NONE);
+        displayPageCommand(componentBuilder, command, page);
+        componentBuilder.append("\n");
+
+        // Display the alphabet index as the header
+        displayAlphabetIndex(componentBuilder, command, firstInstances);
+        sender.spigot().sendMessage(componentBuilder.create());
+    }
+
+    /**
+     * Displays the list of books on the current page
+     *
+     * @param componentBuilder <p>The component builder to append to</p>
+     * @param command          <p>The command used for switching pages</p>
+     * @param page             <p>The current page</p>
+     * @param availableBooks   <p>All available books</p>
+     */
+    protected static void displayBookList(@NotNull ComponentBuilder componentBuilder, @NotNull String command, int page,
+                                          @NotNull List<String> availableBooks) {
+        int startIndex = (page - 1) * booksPerPage;
+        for (int bookIndex = startIndex; bookIndex < Math.min(startIndex + booksPerPage, availableBooks.size()); bookIndex++) {
+            componentBuilder.append("[" + (bookIndex + 1) + "]").color(interactColor).event(
+                    new ClickEvent(ClickEvent.Action.SUGGEST_COMMAND, "/" + command + " " +
+                            (bookIndex + 1))).event(new HoverEvent(HoverEvent.Action.SHOW_TEXT,
+                    new Text("Select book by index")));
+
+            componentBuilder.append(" ", ComponentBuilder.FormatRetention.NONE);
+
+            String[] parts = getNiceName(availableBooks.get(bookIndex)).split(" by ");
+            componentBuilder.append(parts[0]).color(ChatColor.WHITE).event(
+                    new ClickEvent(ClickEvent.Action.SUGGEST_COMMAND, "/" + command + " " +
+                            availableBooks.get(bookIndex))).event(
+                    new HoverEvent(HoverEvent.Action.SHOW_TEXT, new Text("Select book by path")));
+            componentBuilder.append(" by ", ComponentBuilder.FormatRetention.NONE).color(ChatColor.WHITE);
+            componentBuilder.append(parts[1]).color(ChatColor.WHITE).event(
+                    new ClickEvent(ClickEvent.Action.RUN_COMMAND, "/" + command + " author" +
+                            BookFormatter.stripColor(parts[1]) + " page1")).event(
+                    new HoverEvent(HoverEvent.Action.SHOW_TEXT, new Text("Books by " +
+                            BookFormatter.stripColor(parts[1]))));
+            componentBuilder.append("\n");
+        }
+    }
+
+}

src/main/java/net/knarcraft/bookswithoutborders/handler/BookshelfHandler.java

@@ -0,0 +1,145 @@
+package net.knarcraft.bookswithoutborders.handler;
+
+import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import net.knarcraft.bookswithoutborders.container.Bookshelf;
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.World;
+import org.bukkit.configuration.ConfigurationSection;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import java.util.logging.Level;
+
+/**
+ * A handler keeping track of all bookshelves
+ */
+public class BookshelfHandler {
+
+    private static final File bookshelfFile = new File(BooksWithoutBorders.getInstance().getDataFolder(),
+            "bookshelves.yml");
+    private Set<Bookshelf> bookshelves;
+    private Map<Location, Bookshelf> locationLookup;
+
+    /**
+     * Gets a bookshelf from the given location
+     *
+     * @param location <p>The location of the bookshelf</p>
+     * @return <p>The bookshelf at the location, or null if no such bookshelf exists</p>
+     */
+    @Nullable
+    public Bookshelf getFromLocation(@NotNull Location location) {
+        return locationLookup.get(location);
+    }
+
+    /**
+     * Registers the given bookshelf to this handler
+     *
+     * @param bookshelf <p>The bookshelf to register</p>
+     */
+    public void registerBookshelf(@NotNull Bookshelf bookshelf) {
+        this.bookshelves.add(bookshelf);
+        this.locationLookup.put(bookshelf.getLocation(), bookshelf);
+    }
+
+    /**
+     * Unregisters the given bookshelf from this handler
+     *
+     * @param bookshelf <p>The bookshelf to unregister</p>
+     */
+    public void unregisterBookshelf(@NotNull Bookshelf bookshelf) {
+        this.locationLookup.remove(bookshelf.getLocation());
+        this.bookshelves.remove(bookshelf);
+    }
+
+    /**
+     * Loads all stored bookshelves
+     */
+    public void load() {
+        this.bookshelves = new HashSet<>();
+        this.locationLookup = new HashMap<>();
+
+        YamlConfiguration configuration = YamlConfiguration.loadConfiguration(bookshelfFile);
+        ConfigurationSection bookshelfSection = configuration.getConfigurationSection("bookshelves");
+        if (bookshelfSection == null) {
+            BooksWithoutBorders.getInstance().getLogger().log(Level.INFO,
+                    "BooksWithoutBorders found no bookshelves to load");
+            return;
+        }
+
+        for (String key : bookshelfSection.getKeys(false)) {
+            String[] locationInfo = key.split(",");
+            World world = Bukkit.getWorld(UUID.fromString(locationInfo[0]));
+            double x = Integer.parseInt(locationInfo[1]);
+            double y = Integer.parseInt(locationInfo[2]);
+            double z = Integer.parseInt(locationInfo[3]);
+            Location bookshelfLocation = new Location(world, x, y, z);
+
+            String titleKey = key + ".title";
+            String loreKey = key + ".lore";
+
+            String title = bookshelfSection.getString(titleKey, null);
+            List<String> loreStrings = new ArrayList<>();
+            List<?> lore = bookshelfSection.getList(loreKey);
+            if (lore == null) {
+                throw new IllegalArgumentException("Lore is missing from bookshelf data!");
+            }
+            lore.forEach((item) -> {
+                if (item instanceof String) {
+                    loreStrings.add((String) item);
+                }
+            });
+
+            if (title != null) {
+                registerBookshelf(new Bookshelf(bookshelfLocation, title, loreStrings));
+            }
+        }
+    }
+
+    /**
+     * Saves all current bookshelves
+     */
+    public void save() {
+        try {
+            YamlConfiguration configuration = new YamlConfiguration();
+            ConfigurationSection bookshelfSection = configuration.createSection("bookshelves");
+            for (Bookshelf bookshelf : bookshelves) {
+                saveBookshelf(bookshelfSection, bookshelf);
+            }
+            configuration.save(bookshelfFile);
+        } catch (IOException exception) {
+            BooksWithoutBorders.getInstance().getLogger().log(Level.SEVERE, "Unable to save bookshelves!");
+        }
+    }
+
+    /**
+     * Saves a bookshelf to the given configuration section
+     *
+     * @param section   <p>The configuration section to save to</p>
+     * @param bookshelf <p>The bookshelf to save</p>
+     */
+    private void saveBookshelf(@NotNull ConfigurationSection section, @NotNull Bookshelf bookshelf) {
+        Location location = bookshelf.getLocation();
+        if (location.getWorld() == null) {
+            return;
+        }
+
+        String key = location.getWorld().getUID() + "," + location.getBlockX() + "," + location.getBlockY() +
+                "," + location.getBlockZ();
+        String titleKey = key + ".title";
+        String loreKey = key + ".lore";
+        section.set(titleKey, bookshelf.getTitle());
+        section.set(loreKey, bookshelf.getLore());
+    }
+
+}

src/main/java/net/knarcraft/bookswithoutborders/listener/BookEventListener.java

@@ -5,6 +5,7 @@ import net.knarcraft.bookswithoutborders.utility.BookFormatter;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.player.PlayerEditBookEvent;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * A listener for listening to book events
@@ -14,7 +15,7 @@ import org.bukkit.event.player.PlayerEditBookEvent;
 public class BookEventListener implements Listener {
 
     @EventHandler
-    public void onBookSign(PlayerEditBookEvent event) {
+    public void onBookSign(@NotNull PlayerEditBookEvent event) {
         if (event.isCancelled() || !event.isSigning() || !BooksWithoutBordersConfig.formatBooks()) {
             return;
         }

src/main/java/net/knarcraft/bookswithoutborders/listener/BookshelfListener.java

@@ -1,35 +1,58 @@
 package net.knarcraft.bookswithoutborders.listener;
 
+import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
 import net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig;
+import net.knarcraft.bookswithoutborders.container.Bookshelf;
+import net.knarcraft.bookswithoutborders.handler.BookshelfHandler;
 import net.knarcraft.bookswithoutborders.utility.IntegerToRomanConverter;
 import net.md_5.bungee.api.ChatColor;
+import org.bukkit.Location;
+import org.bukkit.Material;
+import org.bukkit.block.Block;
 import org.bukkit.block.ChiseledBookshelf;
 import org.bukkit.enchantments.Enchantment;
 import org.bukkit.entity.Player;
 import org.bukkit.event.Event;
 import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
 import org.bukkit.event.block.Action;
+import org.bukkit.event.block.BlockBreakEvent;
 import org.bukkit.event.player.PlayerInteractEvent;
 import org.bukkit.inventory.ChiseledBookshelfInventory;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
 import org.bukkit.inventory.meta.EnchantmentStorageMeta;
 import org.bukkit.inventory.meta.ItemMeta;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
-import static net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig.getSuccessColor;
-
 /**
  * A listener for bookshelf clicking
  */
 public class BookshelfListener implements Listener {
 
+    @EventHandler(ignoreCancelled = true, priority = EventPriority.MONITOR)
+    public void onBookshelfBreak(@NotNull BlockBreakEvent event) {
+        Block block = event.getBlock();
+
+        if (block.getType() != Material.CHISELED_BOOKSHELF) {
+            return;
+        }
+
+        BookshelfHandler bookshelfHandler = BooksWithoutBorders.getBookshelfHandler();
+        Bookshelf bookshelf = bookshelfHandler.getFromLocation(block.getLocation());
+        if (bookshelf != null) {
+            bookshelfHandler.unregisterBookshelf(bookshelf);
+            bookshelfHandler.save();
+        }
+    }
+
     @EventHandler
-    public void onBookshelfClick(PlayerInteractEvent event) {
+    public void onBookshelfClick(@NotNull PlayerInteractEvent event) {
         Player player = event.getPlayer();
 
         // If left-clicking a chiseled bookshelf and sneaking, display contents
@@ -49,29 +72,53 @@ public class BookshelfListener implements Listener {
         event.setUseItemInHand(Event.Result.DENY);
 
         ChiseledBookshelfInventory bookshelfInventory = chiseledBookshelf.getInventory();
-        player.sendMessage(getBookshelfDescription(bookshelfInventory));
+        player.sendMessage(getBookshelfDescription(bookshelfInventory, event.getClickedBlock().getLocation()));
     }
 
     /**
      * Gets the description for a bookshelf's contents
      *
      * @param bookshelfInventory <p>The inventory of the bookshelf to describe</p>
+     * @param location           <p>The location of the clicked bookshelf</p>
      * @return <p>A textual description of the bookshelf's contents</p>
      */
-    private String getBookshelfDescription(ChiseledBookshelfInventory bookshelfInventory) {
+    @NotNull
-        StringBuilder builder = new StringBuilder(getSuccessColor() + "Books in shelf:");
+    private String getBookshelfDescription(@NotNull ChiseledBookshelfInventory bookshelfInventory, @NotNull Location location) {
-        for (ItemStack itemStack : bookshelfInventory.getStorageContents()) {
+        StringBuilder builder = new StringBuilder();
+
+        Bookshelf bookshelf = BooksWithoutBorders.getBookshelfHandler().getFromLocation(location);
+        if (bookshelf != null) {
+            builder.append(ChatColor.of("#FF5700")).append("Books in ").append(bookshelf.getTitle())
+                    .append(":").append(ChatColor.RESET);
+            for (String lore : bookshelf.getLore()) {
+                builder.append("\n  ").append(ChatColor.LIGHT_PURPLE).append(lore);
+            }
+        } else {
+            builder.append(ChatColor.of("#FF5700")).append("Books in shelf:").append(ChatColor.RESET);
+        }
+
+        for (int i = 0; i < bookshelfInventory.getSize(); i++) {
+            int index = (i % 3) + 1;
+            if (i % 3 == 0) {
+                builder.append("\n ").append(ChatColor.of("#FF5700")).append(
+                        i < 3 ? "Top Row:" : "Bottom Row:").append(ChatColor.RESET);
+            }
+
+            builder.append("\n ").append(ChatColor.of("#ffd700")).append(index).append(". ").append(ChatColor.RESET);
+
+            ItemStack itemStack = bookshelfInventory.getItem(i);
             if (itemStack == null) {
+                builder.append(ChatColor.GRAY).append("<empty>");
                 continue;
             }
             ItemMeta meta = itemStack.getItemMeta();
-            builder.append("\n ").append(ChatColor.GRAY).append(" - ");
+
             if (meta instanceof BookMeta bookMeta) {
                 builder.append(getBookDescription(bookMeta));
             } else if (meta instanceof EnchantmentStorageMeta enchantmentStorageMeta) {
                 builder.append(getEnchantedBookDescription(enchantmentStorageMeta));
             } else if (meta != null) {
-                builder.append(getPlainBookDescription(meta));
+                builder.append(ChatColor.of("#A5682A")).append("[P]").append(ChatColor.RESET).append(getPlainBookDescription(meta));
             }
         }
         return builder.toString();
@@ -83,7 +130,8 @@ public class BookshelfListener implements Listener {
      * @param itemMeta <p>The metadata for the book to describe</p>
      * @return <p>The description of the book</p>
      */
-    private String getPlainBookDescription(ItemMeta itemMeta) {
+    @NotNull
+    private String getPlainBookDescription(@NotNull ItemMeta itemMeta) {
         String name = itemMeta.getDisplayName();
         if (name.isEmpty()) {
             name = "Plain book";
@@ -97,7 +145,8 @@ public class BookshelfListener implements Listener {
      * @param bookMeta <p>The metadata for the book to describe</p>
      * @return <p>The book's description</p>
      */
-    private String getBookDescription(BookMeta bookMeta) {
+    @NotNull
+    private String getBookDescription(@NotNull BookMeta bookMeta) {
         String title;
         String author;
         if (!bookMeta.hasTitle() || bookMeta.getTitle() == null) {
@@ -110,7 +159,7 @@ public class BookshelfListener implements Listener {
         } else {
             author = bookMeta.getAuthor();
         }
-        return title + " by " + author;
+        return ChatColor.of("#686868") + "[Q]" + ChatColor.RESET + title + ChatColor.RESET + " by " + author;
     }
 
     /**
@@ -119,9 +168,10 @@ public class BookshelfListener implements Listener {
      * @param enchantmentStorageMeta <p>The metadata for the enchanted book to describe</p>
      * @return <p>The enchanted book's description</p>
      */
-    private String getEnchantedBookDescription(EnchantmentStorageMeta enchantmentStorageMeta) {
+    @NotNull
+    private String getEnchantedBookDescription(@NotNull EnchantmentStorageMeta enchantmentStorageMeta) {
         StringBuilder builder = new StringBuilder();
-        builder.append("Enchanted book (");
+        builder.append(ChatColor.of("#A64CFF")).append("[E]").append(ChatColor.RESET);
         Map<Enchantment, Integer> enchantmentMap = enchantmentStorageMeta.getStoredEnchants();
         List<String> enchantments = new ArrayList<>(enchantmentMap.size());
         for (Map.Entry<Enchantment, Integer> enchantmentEntry : enchantmentMap.entrySet()) {
@@ -129,7 +179,6 @@ public class BookshelfListener implements Listener {
                     IntegerToRomanConverter.getRomanNumber(enchantmentEntry.getValue()));
         }
         builder.append(String.join(", ", enchantments));
-        builder.append(")");
         return builder.toString();
     }
 
@@ -139,7 +188,8 @@ public class BookshelfListener implements Listener {
      * @param enchantment <p>The enchantment to get the name of</p>
      * @return <p>The prettified enchantment name</p>
      */
-    private String getEnchantmentName(Enchantment enchantment) {
+    @NotNull
+    private String getEnchantmentName(@NotNull Enchantment enchantment) {
         // Note: While depreciated, changing this is incompatible with Paper
         return uppercaseFirst(enchantment.getKey().getKey().replace("_", " "));
     }
@@ -150,7 +200,8 @@ public class BookshelfListener implements Listener {
      * @param input <p>The input to uppercase</p>
      * @return <p>The input string with more uppercase</p>
      */
-    private String uppercaseFirst(String input) {
+    @NotNull
+    private String uppercaseFirst(@NotNull String input) {
         String[] parts = input.split(" ");
         for (int i = 0; i < parts.length; i++) {
             parts[i] = parts[i].substring(0, 1).toUpperCase() + parts[i].substring(1);

src/main/java/net/knarcraft/bookswithoutborders/listener/PlayerEventListener.java

@@ -17,6 +17,8 @@ import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.PlayerInventory;
 import org.bukkit.inventory.meta.BookMeta;
 import org.bukkit.inventory.meta.ItemMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.util.logging.Level;
@@ -29,7 +31,7 @@ public class PlayerEventListener implements Listener {
     private final BooksWithoutBorders booksWithoutBorders = BooksWithoutBorders.getInstance();
 
     @EventHandler
-    public void onHold(PlayerItemHeldEvent event) {
+    public void onHold(@NotNull PlayerItemHeldEvent event) {
         if (event.isCancelled()) {
             return;
         }
@@ -54,7 +56,7 @@ public class PlayerEventListener implements Listener {
     }
 
     @EventHandler
-    public void onPlayerJoin(PlayerJoinEvent event) {
+    public void onPlayerJoin(@NotNull PlayerJoinEvent event) {
         Player player = event.getPlayer();
 
         //If a book directory exists with this player's name, move it to this player's UUID
@@ -82,13 +84,17 @@ public class PlayerEventListener implements Listener {
         ItemStack offHandItem = InventoryHelper.getHeldItem(player, false);
         if (mainHandItem.getType() == Material.WRITTEN_BOOK) {
             ItemMeta itemMetadata = mainHandItem.getItemMeta();
+            if (itemMetadata != null) {
                 updateBookInHand(player, itemMetadata, true);
             }
+        }
         if (offHandItem.getType() == Material.WRITTEN_BOOK) {
             ItemMeta itemMetadata = offHandItem.getItemMeta();
+            if (itemMetadata != null) {
                 updateBookInHand(player, itemMetadata, false);
             }
         }
+    }
 
     /**
      * Gives a book to a player joining for the first time
@@ -98,7 +104,7 @@ public class PlayerEventListener implements Listener {
      * @param sendMessage <p>Whether to send a message to the joining player</p>
      * @return <p>True if a message has yet to be sent</p>
      */
-    private boolean giveBookToNewPlayer(String bookName, Player player, boolean sendMessage) {
+    private boolean giveBookToNewPlayer(@NotNull String bookName, @NotNull Player player, boolean sendMessage) {
         if (!bookName.trim().isEmpty()) {
 
             //Give the book to the player if it exists
@@ -125,7 +131,7 @@ public class PlayerEventListener implements Listener {
      * @param itemMetadata <p>Information about the held book</p>
      * @param mainHand     <p>Whether to update the book in the player's main hand</p>
      */
-    private void updateBookInHand(Player player, ItemMeta itemMetadata, boolean mainHand) {
+    private void updateBookInHand(@NotNull Player player, @NotNull ItemMeta itemMetadata, boolean mainHand) {
         PlayerInventory playerInventory = player.getInventory();
         ItemStack updatedBook = updateBook(player, (BookMeta) itemMetadata);
         if (updatedBook != null) {
@@ -144,7 +150,8 @@ public class PlayerEventListener implements Listener {
      * @param oldBook <p>Metadata about the held book</p>
      * @return <p>An updated book</p>
      */
-    public ItemStack updateBook(Player player, BookMeta oldBook) {
+    @Nullable
+    public ItemStack updateBook(@NotNull Player player, @NotNull BookMeta oldBook) {
         //handles hacked title-less books
         if (oldBook.getTitle() == null || oldBook.getTitle().length() < 3) {
             return null;

src/main/java/net/knarcraft/bookswithoutborders/listener/SignEventListener.java

@@ -4,6 +4,7 @@ import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
 import net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig;
 import net.knarcraft.bookswithoutborders.state.EncryptionStyle;
 import net.knarcraft.bookswithoutborders.utility.BookFileHelper;
+import net.knarcraft.bookswithoutborders.utility.BookFormatter;
 import net.knarcraft.bookswithoutborders.utility.BookLoader;
 import net.knarcraft.bookswithoutborders.utility.EncryptionHelper;
 import net.knarcraft.bookswithoutborders.utility.InputCleaningHelper;
@@ -24,6 +25,8 @@ import org.bukkit.inventory.EquipmentSlot;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.PlayerInventory;
 import org.bukkit.inventory.meta.BookMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 
@@ -39,7 +42,7 @@ public class SignEventListener implements Listener {
     private final String slash = getSlash();
 
     @EventHandler
-    public void onSignChange(SignChangeEvent event) {
+    public void onSignChange(@NotNull SignChangeEvent event) {
         if (event.isCancelled()) {
             return;
         }
@@ -79,7 +82,7 @@ public class SignEventListener implements Listener {
     }
 
     @EventHandler
-    public void onClick(PlayerInteractEvent event) {
+    public void onClick(@NotNull PlayerInteractEvent event) {
         if (event.getClickedBlock() == null) {
             return;
         }
@@ -138,13 +141,14 @@ public class SignEventListener implements Listener {
      * @param player       <p>The player which clicked the sign</p>
      * @param hand         <p>The EquipmentSlot of the used hand</p>
      */
-    private void decryptHeldBookUsingSign(Sign sign, Material heldItemType, Player player, EquipmentSlot hand) {
+    private void decryptHeldBookUsingSign(@NotNull Sign sign, @NotNull Material heldItemType, @NotNull Player player,
+                                          @NotNull EquipmentSlot hand) {
         //Decrypt the held book and replace it
         if (heldItemType == Material.WRITTEN_BOOK) {
             player.closeInventory();
 
             //Converts user supplied key into integer form
-            String lineText = ChatColor.stripColor(sign.getSide(Side.FRONT).getLine(2));
+            String lineText = BookFormatter.stripColor(sign.getSide(Side.FRONT).getLine(2));
             String key = EncryptionHelper.getNumberKeyFromStringKey(lineText);
 
             ItemStack book = EncryptionHelper.loadEncryptedBook(player, key, false);
@@ -161,9 +165,10 @@ public class SignEventListener implements Listener {
      * @param sign <p>The sign to check</p>
      * @return <p>The color of the sign</p>
      */
-    private ChatColor getSignLine2Color(Sign sign) {
+    @Nullable
+    private ChatColor getSignLine2Color(@NotNull Sign sign) {
         String line = sign.getSide(Side.FRONT).getLine(2);
-        if (!ChatColor.stripColor(line).equals(line)) {
+        if (!BookFormatter.stripColor(line).equals(line)) {
             return ChatColor.getByChar(sign.getSide(Side.FRONT).getLine(2).substring(1, 2).charAt(0));
         } else {
             return null;
@@ -179,7 +184,8 @@ public class SignEventListener implements Listener {
      * @param color      <p>The color to match</p>
      * @return <p>True if the given string is what's on the sign</p>
      */
-    private boolean signLineEquals(Sign sign, int lineNumber, String compareTo, ChatColor color) {
+    private boolean signLineEquals(@NotNull Sign sign, int lineNumber, @NotNull String compareTo,
+                                   @NotNull ChatColor color) {
         String line = sign.getSide(Side.FRONT).getLine(lineNumber);
         return line.equalsIgnoreCase(color + compareTo);
     }
@@ -191,7 +197,8 @@ public class SignEventListener implements Listener {
      * @param lines  <p>The lines on the sign</p>
      * @param player <p>The player which edited the sign</p>
      */
-    private void generateGiveSign(SignChangeEvent event, String[] lines, Player player) {
+    private void generateGiveSign(@NotNull SignChangeEvent event, @NotNull String[] lines,
+                                  @NotNull Player player) {
         if (lines[2].length() > 13 || lines[3].length() > 13) {
             BooksWithoutBorders.sendErrorMessage(player,
                     "[Give] signs' 3rd and 4th lines must be 13 characters or less!");
@@ -220,7 +227,7 @@ public class SignEventListener implements Listener {
      * @param event   <p>The event causing the creation of the give sign</p>
      * @param isValid <p>Whether the created sign is valid</p>
      */
-    private void markGiveSignValidity(SignChangeEvent event, boolean isValid) {
+    private void markGiveSignValidity(@NotNull SignChangeEvent event, boolean isValid) {
         String[] lines = event.getLines();
         if (isValid) {
             event.setLine(2, ChatColor.DARK_GREEN + lines[2]);
@@ -239,7 +246,8 @@ public class SignEventListener implements Listener {
      * @param heldItem <p>The type of the held book</p>
      * @param hand     <p>The hand the player is using to hold the book</p>
      */
-    private void decryptBook(BookMeta oldBook, Player player, ItemStack heldItem, EquipmentSlot hand) {
+    private void decryptBook(@NotNull BookMeta oldBook, @NotNull Player player, @NotNull ItemStack heldItem,
+                             @NotNull EquipmentSlot hand) {
         ItemStack newBook;
 
         //Check if the book is encrypted by Books Without Borders
@@ -285,14 +293,15 @@ public class SignEventListener implements Listener {
      * @param player       <p>The player which clicked the sign</p>
      * @param hand         <p>The EquipmentSlot of the used hand</p>
      */
-    private void encryptHeldBookUsingSign(Sign sign, Material heldItemType, Player player, EquipmentSlot hand) {
+    private void encryptHeldBookUsingSign(@NotNull Sign sign, @NotNull Material heldItemType, @NotNull Player player,
+                                          @NotNull EquipmentSlot hand) {
         ItemStack eBook;
         String[] lines = sign.getSide(Side.FRONT).getLines();
         boolean mainHand = hand == EquipmentSlot.HAND;
         if (heldItemType == Material.WRITTEN_BOOK) {
             player.closeInventory();
-            eBook = EncryptionHelper.encryptBook(player, mainHand, ChatColor.stripColor(lines[2]),
+            eBook = EncryptionHelper.encryptBook(player, mainHand, BookFormatter.stripColor(lines[2]),
-                    EncryptionStyle.getFromString(ChatColor.stripColor(lines[3])));
+                    EncryptionStyle.getFromString(BookFormatter.stripColor(lines[3])));
             if (eBook != null) {
                 player.getInventory().setItem(hand, eBook);
             }
@@ -305,8 +314,8 @@ public class SignEventListener implements Listener {
      * @param sign   <p>The sign the user clicked</p>
      * @param player <p>The player which clicked the sign</p>
      */
-    private void giveBook(Sign sign, Player player) {
+    private void giveBook(@NotNull Sign sign, @NotNull Player player) {
-        String fileName = ChatColor.stripColor(sign.getSide(Side.FRONT).getLine(2));
+        String fileName = BookFormatter.stripColor(sign.getSide(Side.FRONT).getLine(2));
         boolean isLoadListNumber = false;
 
         try {
@@ -318,7 +327,7 @@ public class SignEventListener implements Listener {
         //Add the third line to the second line for the full filename
         String thirdLine = sign.getSide(Side.FRONT).getLine(3);
         if (!isLoadListNumber && thirdLine.length() >= 2) {
-            fileName += ChatColor.stripColor(thirdLine);
+            fileName += BookFormatter.stripColor(thirdLine);
         }
 
         ItemStack newBook = BookLoader.loadBook(player, fileName, "true", "public");

src/main/java/net/knarcraft/bookswithoutborders/state/BookDirectory.java

@@ -1,5 +1,8 @@
 package net.knarcraft.bookswithoutborders.state;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 /**
  * This enum represents the different directories books can be saved in
  */
@@ -26,7 +29,8 @@ public enum BookDirectory {
      * @param directory <p>The directory to transform</p>
      * @return <p>A book directory, or null if the given directory is empty</p>
      */
-    public static BookDirectory getFromString(String directory) {
+    @Nullable
+    public static BookDirectory getFromString(@NotNull String directory) {
         if (directory.equalsIgnoreCase("public")) {
             return BookDirectory.PUBLIC;
         } else if (directory.equalsIgnoreCase("player")) {

src/main/java/net/knarcraft/bookswithoutborders/state/EncryptionStyle.java

@@ -1,5 +1,7 @@
 package net.knarcraft.bookswithoutborders.state;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * This enum represents the different available encryption styles
  */
@@ -10,7 +12,7 @@ public enum EncryptionStyle {
 
     private final String name;
 
-    EncryptionStyle(String name) {
+    EncryptionStyle(@NotNull String name) {
         this.name = name;
     }
 
@@ -20,7 +22,8 @@ public enum EncryptionStyle {
      * @param name <p>The name of the encryption style</p>
      * @return <p>An encryption style or null if no match is found</p>
      */
-    public static EncryptionStyle getFromString(String name) {
+    @NotNull
+    public static EncryptionStyle getFromString(@NotNull String name) {
         for (EncryptionStyle style : EncryptionStyle.values()) {
             if (style.name.equalsIgnoreCase(name)) {
                 return style;

src/main/java/net/knarcraft/bookswithoutborders/utility/BookFileHelper.java

@@ -3,12 +3,16 @@ package net.knarcraft.bookswithoutborders.utility;
 import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
 import net.knarcraft.bookswithoutborders.config.BooksWithoutBordersConfig;
 import net.knarcraft.bookswithoutborders.state.BookDirectory;
-import net.md_5.bungee.api.ChatColor;
 import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.regex.Pattern;
 
@@ -28,7 +32,7 @@ public final class BookFileHelper {
      * @param possibleIndex <p>The string which might be a book index</p>
      * @return <p>True if the number is a book index</p>
      */
-    public static boolean isBookListIndex(String possibleIndex) {
+    public static boolean isBookListIndex(@NotNull String possibleIndex) {
         File bookDirectory = new File(getBookFolder().replaceAll("[\\\\/]$", ""));
 
         try {
@@ -49,7 +53,7 @@ public final class BookFileHelper {
      * @param bookFile <p>The path to a book</p>
      * @return <p>True if the file exists and points to a book file</p>
      */
-    public static boolean bookFileExists(String bookFile) {
+    public static boolean bookFileExists(@NotNull String bookFile) {
         return ((new File(bookFile).isFile() && (bookFile.endsWith(".txt") ||
                 bookFile.endsWith(".yml"))) || new File(bookFile + ".txt").isFile() ||
                 new File(bookFile + ".yml").isFile()) && !bookFile.contains("../") && !bookFile.contains("..\\");
@@ -63,7 +67,8 @@ public final class BookFileHelper {
      * @param bookPath <p>The path of the book to get</p>
      * @return <p>The file the path points to, or null otherwise</p>
      */
-    public static File getBookFile(String bookPath) {
+    @Nullable
+    public static File getBookFile(@NotNull String bookPath) {
         if (!bookFileExists(bookPath)) {
             return null;
         }
@@ -93,7 +98,8 @@ public final class BookFileHelper {
      * @param listPublic <p>Whether to list public or personal files</p>
      * @return <p>A list of available files</p>
      */
-    public static List<String> listFiles(CommandSender sender, Boolean listPublic) {
+    @Nullable
+    public static List<String> listFiles(@NotNull CommandSender sender, @NotNull Boolean listPublic) {
         File file = BookHelper.getBookDirectoryPath(listPublic ? BookDirectory.PUBLIC : BookDirectory.PLAYER, sender);
         if (file == null) {
             return new ArrayList<>();
@@ -102,31 +108,23 @@ public final class BookFileHelper {
     }
 
     /**
-     * Prints the available books
+     * Gets a map between characters, and the first instance of a book's title starting with that character
      *
-     * @param sender     <p>The sender to display the books to</p>
+     * @param books <p>The books to look through</p>
-     * @param listPublic <p>Whether to display public books</p>
+     * @return <p>The map of the first index containing each character</p>
      */
-    public static void printBooks(CommandSender sender, boolean listPublic) {
+    @NotNull
-        List<String> availableBooks = BooksWithoutBorders.getAvailableBooks(sender, listPublic);
+    public static Map<Character, Integer> populateLetterIndices(@NotNull List<String> books) {
-        BookFileHelper.printFiles(sender, availableBooks);
+        Map<Character, Integer> firstEncounter = new HashMap<>();
+        Character current = null;
+        for (int i = 0; i < books.size(); i++) {
+            char first = BookFormatter.stripColor(books.get(i)).toLowerCase().charAt(0);
+            if (current == null || current != first) {
+                current = first;
+                firstEncounter.put(first, i);
             }
-
-    /**
-     * Prints a list of files
-     *
-     * @param sender   <p>The command sender to show the list to</p>
-     * @param fileList <p>The files to list</p>
-     */
-    public static void printFiles(CommandSender sender, List<String> fileList) {
-        BooksWithoutBorders.sendSuccessMessage(sender, "Available Books:");
-        if (fileList == null) {
-            return;
-        }
-        int listSize = fileList.size();
-        for (int fileIndex = 0; fileIndex < listSize; fileIndex++) {
-            sender.sendMessage(ChatColor.GRAY + "[" + (fileIndex + 1) + "] " + fileList.get(fileIndex));
         }
+        return firstEncounter;
     }
 
     /**
@@ -136,7 +134,8 @@ public final class BookFileHelper {
      * @param searchDirectory <p>The directory to search for files</p>
      * @return <p>A list of available files</p>
      */
-    private static List<String> listFiles(CommandSender sender, File searchDirectory) {
+    @Nullable
+    private static List<String> listFiles(@NotNull CommandSender sender, @NotNull File searchDirectory) {
         List<String> fileList = new ArrayList<>();
         File[] existingFiles = searchDirectory.listFiles();
 
@@ -146,7 +145,8 @@ public final class BookFileHelper {
         }
 
         for (File foundFile : existingFiles) {
-            if (!foundFile.isFile()) {
+            // Filter out invalid files
+            if (!foundFile.isFile() || foundFile.getName().contains(" ") || foundFile.getName().contains("§")) {
                 continue;
             }
             String fileName = foundFile.getName();
@@ -163,6 +163,10 @@ public final class BookFileHelper {
             }
         }
 
+        // Sort the book list
+        Comparator<String> bookComparator = Comparator.naturalOrder();
+        fileList.sort((a, b) -> bookComparator.compare(BookFormatter.stripColor(a).toLowerCase(),
+                BookFormatter.stripColor(b).toLowerCase()));
         return fileList;
     }
 
@@ -173,7 +177,7 @@ public final class BookFileHelper {
      * @param fileName   <p>The name of the file which might already exist</p>
      * @return <p>The number of found duplicates</p>
      */
-    public static int findDuplicates(File[] foundFiles, String fileName) {
+    public static int findDuplicates(@NotNull File[] foundFiles, @NotNull String fileName) {
         int foundDuplicates = 0;
         for (File foundFile : foundFiles) {
             if (foundFile.getName().matches("(\\([0-9]+\\))?" + Pattern.quote(fileName) + "(\\.yml|\\.txt)?")) {

src/main/java/net/knarcraft/bookswithoutborders/utility/BookFormatter.java

@@ -3,6 +3,7 @@ package net.knarcraft.bookswithoutborders.utility;
 import net.knarcraft.knarlib.property.ColorConversion;
 import net.knarcraft.knarlib.util.ColorHelper;
 import org.bukkit.inventory.meta.BookMeta;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -24,7 +25,7 @@ public final class BookFormatter {
      *
      * @param rawPages <p>A list of pages</p>
      */
-    public static void formatLastPage(List<String> rawPages) {
+    public static void formatLastPage(@NotNull List<String> rawPages) {
         int maxPageText = 256;
         int fitsNewline = maxPageText - 2;
 
@@ -49,7 +50,7 @@ public final class BookFormatter {
      * @param maxPageText <p>The max number of characters which fit on a page</p>
      * @param fitsNewline <p>The max number of characters on a page which still fits a newline character</p>
      */
-    public static void formatLastPageSplitOverflow(List<String> rawPages, int maxPageText, int fitsNewline) {
+    public static void formatLastPageSplitOverflow(@NotNull List<String> rawPages, int maxPageText, int fitsNewline) {
         while (rawPages.get(rawPages.size() - 1).length() > maxPageText) {
             int splitPosition;
             String fittingText = rawPages.get(rawPages.size() - 1).substring(0, maxPageText);
@@ -77,7 +78,7 @@ public final class BookFormatter {
      * @param rawPages    <p>The raw pages to format</p>
      * @param maxPageText <p>The max number of characters which fit on a page</p>
      */
-    public static void formatLastPageCombinePages(List<String> rawPages, int maxPageText) {
+    public static void formatLastPageCombinePages(@NotNull List<String> rawPages, int maxPageText) {
         int lastPageIndex = rawPages.size() - 1;
         int nextToLastIndex = rawPages.size() - 2;
         if (rawPages.get(nextToLastIndex).length() + rawPages.get(lastPageIndex).length() <= maxPageText) {
@@ -92,7 +93,7 @@ public final class BookFormatter {
      * @param rawPages    <p>The raw pages to format</p>
      * @param fitsNewline <p>The max number of characters on a page which still fits a newline character</p>
      */
-    public static void formatLastPageAddNewline(List<String> rawPages, int fitsNewline) {
+    public static void formatLastPageAddNewline(@NotNull List<String> rawPages, int fitsNewline) {
         int pageIndex = rawPages.size() - 1;
         if (rawPages.get(pageIndex).length() <= fitsNewline && !rawPages.get(pageIndex).isEmpty()) {
             rawPages.set(pageIndex, (rawPages.get(pageIndex)) + "\n");
@@ -105,7 +106,8 @@ public final class BookFormatter {
      * @param bookMeta <p>The book meta to change</p>
      * @return <p>The changed book meta</p>
      */
-    public static BookMeta formatPages(BookMeta bookMeta) {
+    @NotNull
+    public static BookMeta formatPages(@NotNull BookMeta bookMeta) {
         List<String> formattedPages = new ArrayList<>(Objects.requireNonNull(bookMeta).getPageCount());
         for (String page : bookMeta.getPages()) {
             formattedPages.add(ColorHelper.translateColorCodes(page, ColorConversion.RGB));
@@ -114,4 +116,15 @@ public final class BookFormatter {
         return bookMeta;
     }
 
+    /**
+     * Strips the color from the given input
+     *
+     * @param input <p>The input to strip</p>
+     * @return <p>The color stripped input</p>
+     */
+    @NotNull
+    public static String stripColor(@NotNull String input) {
+        return ColorHelper.stripColorCodes(input, ColorConversion.RGB);
+    }
+
 }

src/main/java/net/knarcraft/bookswithoutborders/utility/BookHelper.java

@@ -8,6 +8,8 @@ import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.util.UUID;
@@ -31,7 +33,8 @@ public final class BookHelper {
      * @param author <p>The author string</p>
      * @return <p>The author string, converted if it was a UUID</p>
      */
-    public static String authorFromUUID(String author) {
+    @NotNull
+    public static String authorFromUUID(@NotNull String author) {
         try {
             UUID authorID = UUID.fromString(author);
             Player player = Bukkit.getPlayer(authorID);
@@ -50,7 +53,8 @@ public final class BookHelper {
      * @param sender        <p>The command sender trying to get the directory</p>
      * @return <p>The path of the directory, or null if not possible to get</p>
      */
-    public static File getBookDirectoryPath(BookDirectory bookDirectory, CommandSender sender) {
+    @Nullable
+    public static File getBookDirectoryPath(@NotNull BookDirectory bookDirectory, @NotNull CommandSender sender) {
         String bookFolderString = getBookDirectoryPathString(bookDirectory, sender);
         if (bookFolderString == null) {
             return null;
@@ -65,7 +69,8 @@ public final class BookHelper {
      * @param sender        <p>The command sender trying to get the directory</p>
      * @return <p>The path of the directory, or null if not possible to get</p>
      */
-    public static String getBookDirectoryPathString(BookDirectory bookDirectory, CommandSender sender) {
+    @Nullable
+    public static String getBookDirectoryPathString(@NotNull BookDirectory bookDirectory, @NotNull CommandSender sender) {
         String folder = null;
         String bookFolder = BooksWithoutBordersConfig.getBookFolder();
         if (bookDirectory == BookDirectory.PUBLIC) {
@@ -81,7 +86,7 @@ public final class BookHelper {
      *
      * @param bookItem <p>The book item to increase the generation of</p>
      */
-    public static void increaseGeneration(ItemStack bookItem) {
+    public static void increaseGeneration(@NotNull ItemStack bookItem) {
         BookMeta bookMeta = (BookMeta) bookItem.getItemMeta();
         if (BooksWithoutBordersConfig.changeGenerationOnCopy() && bookMeta != null) {
             bookMeta.setGeneration(BookHelper.getNextGeneration(bookMeta.getGeneration()));
@@ -98,7 +103,8 @@ public final class BookHelper {
      * @param currentGeneration <p>The current generation of the book</p>
      * @return <p>The next generation of the book</p>
      */
-    public static BookMeta.Generation getNextGeneration(BookMeta.Generation currentGeneration) {
+    @NotNull
+    public static BookMeta.Generation getNextGeneration(@Nullable BookMeta.Generation currentGeneration) {
         if (currentGeneration == null) {
             return BookMeta.Generation.COPY_OF_ORIGINAL;
         }
@@ -115,12 +121,17 @@ public final class BookHelper {
      * @param book   <p>The book to get the file of</p>
      * @param player <p>The player trying to do something with the book</p>
      * @return <p>The book file</p>
+     * @throws IllegalArgumentException <p>If the book title or author contains the title author separator</p>
      */
-    public static String getBookFile(BookMeta book, Player player, boolean isPublic) {
+    @NotNull
+    public static String getBookFile(@NotNull BookMeta book, @NotNull Player player, boolean isPublic) throws IllegalArgumentException {
         String titleAuthorSeparator = BooksWithoutBordersConfig.getTitleAuthorSeparator();
         String bookName;
         if (book.hasTitle()) {
             bookName = book.getTitle();
+            if (bookName == null) {
+                bookName = "Untitled";
+            }
         } else {
             bookName = "Untitled";
         }
@@ -133,6 +144,14 @@ public final class BookHelper {
             authorName = player.getName();
         } else {
             authorName = book.getAuthor();
+            if (authorName == null) {
+                authorName = "Unknown";
+            }
+        }
+
+        if (bookName.contains(titleAuthorSeparator) || authorName.contains(titleAuthorSeparator)) {
+            throw new IllegalArgumentException("The author or title contains the title author separator. Saving this " +
+                    "book would lead to unexpected problems.");
         }
 
         return fixName(cleanString(bookName + titleAuthorSeparator + authorName), false);
@@ -145,7 +164,7 @@ public final class BookHelper {
      * @param book   <p>The book to check</p>
      * @return <p>True if the player is not the book's author</p>
      */
-    public static boolean isNotAuthor(Player player, BookMeta book) {
+    public static boolean isNotAuthor(@NotNull Player player, @NotNull BookMeta book) {
         if (isAuthor(player.getName(), book.getAuthor())) {
             return false;
         } else {
@@ -162,7 +181,7 @@ public final class BookHelper {
      * @param author     <p>The author to check</p>
      * @return <p>True if the player is the author</p>
      */
-    private static boolean isAuthor(String playerName, String author) {
+    private static boolean isAuthor(@NotNull String playerName, @Nullable String author) {
         playerName = InputCleaningHelper.cleanString(playerName);
         return author != null && playerName.equalsIgnoreCase(InputCleaningHelper.cleanString(author));
     }

src/main/java/net/knarcraft/bookswithoutborders/utility/BookLoader.java

@@ -9,6 +9,8 @@ import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.util.ArrayList;
@@ -31,7 +33,9 @@ public final class BookLoader {
      * @param directory <p>The directory to save the book in</p>
      * @return <p>The loaded book</p>
      */
-    public static ItemStack loadBook(CommandSender sender, String fileName, String isSigned, String directory) {
+    @Nullable
+    public static ItemStack loadBook(@NotNull CommandSender sender, @NotNull String fileName, @NotNull String isSigned,
+                                     @NotNull String directory) {
         return loadBook(sender, fileName, isSigned, directory, 1);
     }
 
@@ -45,8 +49,14 @@ public final class BookLoader {
      * @param numCopies <p>The number of copies to load</p>
      * @return <p>The loaded book</p>
      */
-    public static ItemStack loadBook(CommandSender sender, String fileName, String isSigned, String directory, int numCopies) {
+    @Nullable
+    public static ItemStack loadBook(@NotNull CommandSender sender, @NotNull String fileName, @NotNull String isSigned,
+                                     @NotNull String directory, int numCopies) {
         BookDirectory bookDirectory = BookDirectory.getFromString(directory);
+        if (bookDirectory == null) {
+            BooksWithoutBorders.sendErrorMessage(sender, "Unrecognized book directory!");
+            return null;
+        }
 
         //Find the filename if a book index is given
         try {
@@ -96,8 +106,13 @@ public final class BookLoader {
             book = new ItemStack(Material.WRITABLE_BOOK);
         }
 
+        if (bookMetadata == null) {
+            BooksWithoutBorders.sendErrorMessage(sender, "Unable to create blank book metadata!");
+            return null;
+        }
+
         //Load the book from the given file
-        BookToFromTextHelper.bookFromFile(file, bookMetadata);
+        bookMetadata = BookToFromTextHelper.bookFromFile(file, bookMetadata);
         if (bookMetadata == null) {
             BooksWithoutBorders.sendErrorMessage(sender, "File was blank!!");
             return null;
@@ -131,7 +146,9 @@ public final class BookLoader {
      * @param directory     <p>The relative directory given</p>
      * @return <p>A file or null if it does not exist</p>
      */
-    private static File getFullPath(CommandSender sender, String fileName, BookDirectory bookDirectory, String directory) {
+    @Nullable
+    private static File getFullPath(@NotNull CommandSender sender, @NotNull String fileName,
+                                    @NotNull BookDirectory bookDirectory, @NotNull String directory) {
         File file;
         String slash = BooksWithoutBordersConfig.getSlash();
         String bookFolder = BooksWithoutBordersConfig.getBookFolder();

src/main/java/net/knarcraft/bookswithoutborders/utility/BookToFromTextHelper.java

@@ -6,6 +6,8 @@ import net.knarcraft.knarlib.util.FileHelper;
 import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.configuration.file.YamlConfiguration;
 import org.bukkit.inventory.meta.BookMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.BufferedReader;
 import java.io.File;
@@ -37,7 +39,7 @@ public final class BookToFromTextHelper {
      * @param bookMetadata <p>Metadata about the book to save</p>
      * @throws IOException <p>If unable to save the book</p>
      */
-    public static void bookToYml(String path, String fileName, BookMeta bookMetadata) throws IOException {
+    public static void bookToYml(@NotNull String path, @NotNull String fileName, @NotNull BookMeta bookMetadata) throws IOException {
         FileConfiguration bookYml = YamlConfiguration.loadConfiguration(new File(path, "blank"));
 
         if (bookMetadata.hasTitle()) {
@@ -58,7 +60,7 @@ public final class BookToFromTextHelper {
             bookYml.set("Lore", bookMetadata.getLore());
         }
 
-        bookYml.save(path + fileName + ".yml");
+        bookYml.save(path + InputCleaningHelper.cleanString(fileName) + ".yml");
     }
 
     /**
@@ -68,7 +70,8 @@ public final class BookToFromTextHelper {
      * @param bookMetadata <p>The book metadata to use for saving the book</p>
      * @return <p>The book metadata of the loaded book</p>
      */
-    public static BookMeta bookFromFile(File file, BookMeta bookMetadata) {
+    @Nullable
+    public static BookMeta bookFromFile(@NotNull File file, @NotNull BookMeta bookMetadata) {
         if (file.getName().endsWith(".txt")) {
             return bookFromTXT(file.getName(), file, bookMetadata);
         } else if (file.getName().endsWith(".yml")) {
@@ -86,8 +89,8 @@ public final class BookToFromTextHelper {
      * @param bookMetadata <p>Metadata about the book to save</p>
      * @throws IOException <p>If unable to save the book</p>
      */
-    public static void bookToTXT(String folderPath, String fileName, BookMeta bookMetadata) throws IOException {
+    public static void bookToTXT(@NotNull String folderPath, @NotNull String fileName, @NotNull BookMeta bookMetadata) throws IOException {
-        FileWriter fileWriter = new FileWriter(folderPath + fileName + ".txt", StandardCharsets.UTF_8);
+        FileWriter fileWriter = new FileWriter(folderPath + InputCleaningHelper.cleanString(fileName) + ".txt", StandardCharsets.UTF_8);
         PrintWriter printWriter = new PrintWriter(fileWriter);
         List<String> pages = bookMetadata.getPages();
 
@@ -112,7 +115,8 @@ public final class BookToFromTextHelper {
      * @param bookMetadata <p>Metadata which will be altered with the book's contents</p>
      * @return <p>Metadata for the loaded book</p>
      */
-    private static BookMeta bookFromYml(File file, BookMeta bookMetadata) {
+    @Nullable
+    private static BookMeta bookFromYml(@NotNull File file, @NotNull BookMeta bookMetadata) {
         try {
             FileConfiguration bookYml = YamlConfiguration.loadConfiguration(file);
 
@@ -135,7 +139,8 @@ public final class BookToFromTextHelper {
      * @param bookMetadata <p>Metadata which will be altered with the book's contents</p>
      * @return <p>Metadata for the loaded book</p>
      */
-    private static BookMeta bookFromTXT(String fileName, File file, BookMeta bookMetadata) {
+    @Nullable
+    private static BookMeta bookFromTXT(@NotNull String fileName, @NotNull File file, @NotNull BookMeta bookMetadata) {
         String author;
         String title;
         String titleAuthorSeparator = BooksWithoutBordersConfig.getTitleAuthorSeparator();
@@ -159,13 +164,17 @@ public final class BookToFromTextHelper {
         List<String> rawPages;
         try {
             rawPages = readTextFile(file);
+            if (rawPages == null) {
+                BooksWithoutBorders.getInstance().getLogger().log(Level.SEVERE, "Text file's first line was null");
+                return null;
+            }
         } catch (IOException exception) {
             BooksWithoutBorders.getInstance().getLogger().log(Level.SEVERE, "Unable to read text file");
             return null;
         }
 
         //Parse the generation from the book data
-        if (rawPages != null && !rawPages.isEmpty() && rawPages.get(0).startsWith("Generation:")) {
+        if (!rawPages.isEmpty() && rawPages.get(0).startsWith("Generation:")) {
             bookMetadata.setGeneration(BookMeta.Generation.valueOf(rawPages.get(0).split(":")[1]));
             rawPages.remove(0);
         }
@@ -188,7 +197,8 @@ public final class BookToFromTextHelper {
      * @return <p>A string list where each string is the text on one page</p>
      * @throws IOException <p>If unable to read from the file</p>
      */
-    private static List<String> readTextFile(File file) throws IOException {
+    @Nullable
+    private static List<String> readTextFile(@NotNull File file) throws IOException {
         List<String> rawPages = new ArrayList<>();
         BufferedReader bufferedReader = FileHelper.getBufferedReaderFromInputStream(new FileInputStream(file));
 

src/main/java/net/knarcraft/bookswithoutborders/utility/EconomyHelper.java

@@ -12,6 +12,7 @@ import org.bukkit.inventory.meta.BookMeta;
 import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.RegisteredServiceProvider;
 import org.bukkit.plugin.ServicesManager;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -32,6 +33,7 @@ public final class EconomyHelper {
      *
      * @return <p>An economy instance, or null if it's not initialized</p>
      */
+    @NotNull
     public static Economy getEconomy() {
         return economy;
     }
@@ -67,7 +69,7 @@ public final class EconomyHelper {
      * @param numCopies <p>The number of copies the player is trying to print</p>
      * @return <p>True if the player cannot pay for the printing of the books</p>
      */
-    public static boolean cannotPayForBookPrinting(Player player, int numCopies) {
+    public static boolean cannotPayForBookPrinting(@NotNull Player player, int numCopies) {
         //BookPriceQuantity: How many items are required to pay for each book
         //BookPriceType: Which item is used to pay for the books. AIR = use economy
         Material bookCurrency = BooksWithoutBordersConfig.getBookPriceType();
@@ -100,7 +102,7 @@ public final class EconomyHelper {
      * @param itemCost <p>The number of writable books to pay</p>
      * @return <p>True if the payment was successful</p>
      */
-    private static boolean takeWritableBookPayment(Player player, int itemCost) {
+    private static boolean takeWritableBookPayment(@NotNull Player player, int itemCost) {
         List<ItemStack> books = getPlayersEmptyBooks(player);
         if (countItems(books) < itemCost) {
             BooksWithoutBorders.sendErrorMessage(player, itemCost + " empty " + Material.WRITABLE_BOOK +
@@ -131,7 +133,7 @@ public final class EconomyHelper {
      * @param items <p>The items to count</p>
      * @return <p>The total number of items</p>
      */
-    private static int countItems(List<ItemStack> items) {
+    private static int countItems(@NotNull List<ItemStack> items) {
         int totalItems = 0;
         for (ItemStack itemStack : items) {
             totalItems += itemStack.getAmount();
@@ -145,7 +147,8 @@ public final class EconomyHelper {
      * @param player <p>The player to get books for</p>
      * @return <p>The empty books in the player's inventory</p>
      */
-    private static List<ItemStack> getPlayersEmptyBooks(Player player) {
+    @NotNull
+    private static List<ItemStack> getPlayersEmptyBooks(@NotNull Player player) {
         List<ItemStack> validBooks = new ArrayList<>();
         for (ItemStack itemStack : player.getInventory().getContents()) {
             if (itemStack == null || itemStack.getType() != Material.WRITABLE_BOOK) {
@@ -168,7 +171,7 @@ public final class EconomyHelper {
      * @param numCopies <p>The number of books the player is printing</p>
      * @return <p>True if the player had the money and it has been withdrawn</p>
      */
-    private static boolean payForBookPrintingEconomy(Player player, double cost, int numCopies) {
+    private static boolean payForBookPrintingEconomy(@NotNull Player player, double cost, int numCopies) {
         if ((economy.getBalance(player) - cost) >= 0) {
             economy.withdrawPlayer(player, cost);
             BooksWithoutBorders.sendSuccessMessage(player, economy.format(cost) + " withdrawn to create " +
@@ -188,7 +191,7 @@ public final class EconomyHelper {
      * @param player   <p>The player which needs to pay</p>
      * @param itemCost <p>The number of items to pay</p>
      */
-    private static void payForBookPrintingItem(Player player, int itemCost) {
+    private static void payForBookPrintingItem(@NotNull Player player, int itemCost) {
         PlayerInventory playerInventory = player.getInventory();
 
         int clearedAmount = 0;

src/main/java/net/knarcraft/bookswithoutborders/utility/EncryptionHelper.java

@@ -11,6 +11,8 @@ import org.bukkit.command.ConsoleCommandSender;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
 import java.io.IOException;
@@ -37,7 +39,8 @@ public final class EncryptionHelper {
      * @param key <p>The key to transform</p>
      * @return <p>The numbers representing the key's characters</p>
      */
-    public static String getNumberKeyFromStringKey(String key) {
+    @NotNull
+    public static String getNumberKeyFromStringKey(@NotNull String key) {
         StringBuilder integerKey = new StringBuilder();
         for (int x = 0; x < key.length(); x++) {
             integerKey.append(Character.getNumericValue(Character.codePointAt(key, x)));
@@ -54,7 +57,9 @@ public final class EncryptionHelper {
      * @param player     <p>The player trying to encrypt a book</p>
      * @return <p>The pages of the book in encrypted form</p>
      */
-    public static List<String> encryptBookPages(BookMeta book, EncryptionStyle style, String integerKey, Player player) {
+    @Nullable
+    public static List<String> encryptBookPages(@NotNull BookMeta book, @NotNull EncryptionStyle style,
+                                                @NotNull String integerKey, @NotNull Player player) {
         List<String> encryptedPages = new ArrayList<>();
         //Scramble the book's contents
         if (style == EncryptionStyle.DNA) {
@@ -86,7 +91,9 @@ public final class EncryptionHelper {
      * @param style    <p>The encryption style to use</p>
      * @return <p>An encrypted version of the book</p>
      */
-    public static ItemStack encryptBook(Player player, boolean mainHand, String key, EncryptionStyle style) {
+    @Nullable
+    public static ItemStack encryptBook(@NotNull Player player, boolean mainHand, @NotNull String key,
+                                        @NotNull EncryptionStyle style) {
         return encryptBook(player, mainHand, key, style, "");
     }
 
@@ -100,11 +107,17 @@ public final class EncryptionHelper {
      * @param groupName <p>The name of the group to encrypt for, or "" otherwise</p>
      * @return <p>An encrypted version of the book</p>
      */
-    public static ItemStack encryptBook(Player player, boolean mainHand, String key, EncryptionStyle style, String groupName) {
+    @Nullable
+    public static ItemStack encryptBook(Player player, boolean mainHand, @NotNull String key,
+                                        @NotNull EncryptionStyle style, @NotNull String groupName) {
         //converts user supplied key into integer form
         String integerKey = EncryptionHelper.getNumberKeyFromStringKey(key);
 
         BookMeta book = InventoryHelper.getHeldBookMetadata(player, mainHand);
+        if (book == null) {
+            BooksWithoutBorders.sendErrorMessage(player, "Unable to get metadata from the held book!");
+            return null;
+        }
 
         if (!book.hasPages()) {
             BooksWithoutBorders.sendErrorMessage(player, "Book is empty!");
@@ -143,7 +156,9 @@ public final class EncryptionHelper {
      * @param newMetadata <p>The new metadata of the book</p>
      * @return <p>An encrypted version of the book</p>
      */
-    private static ItemStack createEncryptedBook(BookMeta book, List<String> newPages, Player player, BookMeta newMetadata) {
+    @NotNull
+    private static ItemStack createEncryptedBook(@NotNull BookMeta book, @NotNull List<String> newPages,
+                                                 @NotNull Player player, @NotNull BookMeta newMetadata) {
         //Create the encrypted book
         ItemStack encryptedBook = new ItemStack(Material.WRITTEN_BOOK);
         book.setPages(newPages);
@@ -166,7 +181,9 @@ public final class EncryptionHelper {
      * @param integerKey <p>The key used to encrypt the book</p>
      * @return <p>The new metadata for the book, or null if it could not be saved</p>
      */
-    private static BookMeta saveBookPlaintext(String groupName, Player player, BookMeta book, String integerKey) {
+    @Nullable
+    private static BookMeta saveBookPlaintext(@NotNull String groupName, @NotNull Player player,
+                                              @NotNull BookMeta book, @NotNull String integerKey) {
         BookMeta newMetadata = book;
         boolean wasSaved;
         if (groupName.trim().isEmpty()) {
@@ -190,7 +207,8 @@ public final class EncryptionHelper {
      * @param deleteEncryptedFile <p>Whether to delete the plaintext file after decryption is finished</p>
      * @return <p>The loaded book, or null if no book could be loaded</p>
      */
-    public static ItemStack loadEncryptedBook(Player player, String key, boolean deleteEncryptedFile) {
+    @Nullable
+    public static ItemStack loadEncryptedBook(@NotNull Player player, @NotNull String key, boolean deleteEncryptedFile) {
         ItemStack heldBook = InventoryHelper.getHeldBook(player, true);
         BookMeta bookMetadata = (BookMeta) heldBook.getItemMeta();
         String path = getBookFolder() + "Encrypted" + getSlash();
@@ -246,7 +264,9 @@ public final class EncryptionHelper {
      * @param groupName    <p>The group which should be able to decrypt the book</p>
      * @return <p>The new encrypted metadata for the book, or null if encryption failed</p>
      */
-    private static BookMeta saveEncryptedBookForGroup(Player player, BookMeta bookMetadata, String groupName) {
+    @Nullable
+    private static BookMeta saveEncryptedBookForGroup(@NotNull Player player, @NotNull BookMeta bookMetadata,
+                                                      @NotNull String groupName) {
         String path = getBookFolder() + "Encrypted" + getSlash() + cleanString(groupName) + getSlash();
         File dirTest = new File(path);
         //Creates group dir
@@ -297,7 +317,8 @@ public final class EncryptionHelper {
      * @param key          <p>The key to use for encryption</p>
      * @return <p>The new encrypted metadata for the book, or null if encryption failed</p>
      */
-    private static Boolean saveEncryptedBook(Player player, BookMeta bookMetaData, String key) {
+    @NotNull
+    private static Boolean saveEncryptedBook(@NotNull Player player, @NotNull BookMeta bookMetaData, @NotNull String key) {
         String path = getBookFolder() + "Encrypted" + getSlash();
 
         String fileName = "[" + key + "]" + BookHelper.getBookFile(bookMetaData, player, true);

src/main/java/net/knarcraft/bookswithoutborders/utility/InputCleaningHelper.java

@@ -1,7 +1,12 @@
 package net.knarcraft.bookswithoutborders.utility;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
 import java.util.ArrayList;
 import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * Helper class for cleaning input and names
@@ -17,7 +22,8 @@ public final class InputCleaningHelper {
      * @param list <p>The list to clean</p>
      * @return <p>A clean list containing all relevant values</p>
      */
-    public static List<String> cleanList(List<String> list) {
+    @NotNull
+    public static List<String> cleanList(@NotNull List<String> list) {
         List<String> resultList = new ArrayList<>(list);
         resultList.removeIf((item) -> item == null || item.trim().isEmpty());
         return resultList;
@@ -29,7 +35,8 @@ public final class InputCleaningHelper {
      * @param fileName <p>The file name to clean</p>
      * @return <p>The cleaned file name</p>
      */
-    public static String cleanString(String fileName) {
+    @NotNull
+    public static String cleanString(@NotNull String fileName) {
         fileName = fileName.replace("/", "");
         fileName = fileName.replace("\\", "");
         fileName = fileName.replace("*", "");
@@ -39,6 +46,7 @@ public final class InputCleaningHelper {
         fileName = fileName.replace(">", "");
         fileName = fileName.replace("?", "");
         fileName = fileName.replace("\"", "");
+        fileName = fileName.replace("§", "&");
         return fileName;
     }
 
@@ -49,7 +57,8 @@ public final class InputCleaningHelper {
      * @param isLoading <p>Whether loading from a file as opposed to saving to a file</p>
      * @return <p>The fixed name</p>
      */
-    public static String fixName(String fileName, Boolean isLoading) {
+    @NotNull
+    public static String fixName(@NotNull String fileName, @NotNull Boolean isLoading) {
         if (isLoading) {
             fileName = fileName.replace("_", " ");
         } else {
@@ -58,4 +67,41 @@ public final class InputCleaningHelper {
         return fileName;
     }
 
+    /**
+     * Parses a page number for a string like "page1"
+     *
+     * @param input <p>The input to parse</p>
+     * @return <p>The page number, or 0 if not valid</p>
+     */
+    public static int parsePageNumber(@NotNull String input) {
+        try {
+            Pattern pattern = Pattern.compile("page([0-9]+)");
+            Matcher matcher = pattern.matcher(input);
+            if (matcher.matches()) {
+                return Integer.parseInt(matcher.group(1));
+            } else {
+                return 0;
+            }
+        } catch (NumberFormatException exception) {
+            return 0;
+        }
+    }
+
+    /**
+     * Parses an author specifier given in a command
+     *
+     * @param input <p>The input to parse</p>
+     * @return <p>The author name, or null if not an author specifier</p>
+     */
+    @Nullable
+    public static String parseAuthorSpecifier(@NotNull String input) {
+        Pattern pattern = Pattern.compile("author([0-9a-zA-Z_]+)");
+        Matcher matcher = pattern.matcher(input);
+        if (matcher.matches()) {
+            return matcher.group(1);
+        } else {
+            return null;
+        }
+    }
+
 }

src/main/java/net/knarcraft/bookswithoutborders/utility/IntegerToRomanConverter.java

@@ -1,5 +1,7 @@
 package net.knarcraft.bookswithoutborders.utility;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -40,6 +42,7 @@ public final class IntegerToRomanConverter {
      * @param number <p>The number to convert</p>
      * @return <p>The roman representation of the number</p>
      */
+    @NotNull
     public static String getRomanNumber(int number) {
         StringBuilder output = new StringBuilder();
         int remainder = number;
@@ -83,6 +86,7 @@ public final class IntegerToRomanConverter {
      * @param times     <p>The number of times to repeat the character</p>
      * @return <p>The repeated string</p>
      */
+    @NotNull
     private static String repeat(char character, int times) {
         return String.valueOf(character).repeat(Math.max(0, times));
     }

src/main/java/net/knarcraft/bookswithoutborders/utility/InventoryHelper.java

@@ -7,6 +7,8 @@ import org.bukkit.Material;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.BookMeta;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * The inventory helper mainly helps with getting and setting books
@@ -23,7 +25,8 @@ public final class InventoryHelper {
      * @param signedBook <p>Whether to check for signed or unsigned books</p>
      * @return <p>The book the player is holding</p>
      */
-    public static ItemStack getHeldBook(Player player, boolean signedBook) {
+    @NotNull
+    public static ItemStack getHeldBook(@NotNull Player player, boolean signedBook) {
         ItemSlot heldSlot = getHeldSlotBook(player, false, false, true, signedBook);
         if (heldSlot == ItemSlot.MAIN_HAND) {
             return getHeldItem(player, true);
@@ -40,7 +43,7 @@ public final class InventoryHelper {
      * @param player  <p>The player holding the book</p>
      * @param newBook <p>The new book the player should hold</p>
      */
-    public static void setHeldWrittenBook(Player player, ItemStack newBook) {
+    public static void setHeldWrittenBook(@NotNull Player player, @NotNull ItemStack newBook) {
         ItemSlot itemSlot = getHeldSlotBook(player, false, false, true, true);
         if (itemSlot == ItemSlot.MAIN_HAND) {
             replaceHeldItem(player, newBook, true);
@@ -59,7 +62,8 @@ public final class InventoryHelper {
      * @param twoBooksMessage <p>The message to display if the player is holding one book in each hand</p>
      * @return <p>False if the player is holding exactly one book</p>
      */
-    public static boolean notHoldingOneWritableBookCheck(Player player, String noBookMessage, String twoBooksMessage) {
+    public static boolean notHoldingOneWritableBookCheck(@NotNull Player player, @NotNull String noBookMessage,
+                                                         @NotNull String twoBooksMessage) {
         BookHoldingState holdingState = getBookHoldingState(player);
 
         if (holdingState == BookHoldingState.NONE || holdingState == BookHoldingState.SIGNED_BOTH_HANDS ||
@@ -84,7 +88,8 @@ public final class InventoryHelper {
      * @param twoBooksMessage <p>The message to display if the player is holding one book in each hand</p>
      * @return <p>False if the player is holding exactly one book</p>
      */
-    public static boolean notHoldingOneWrittenBookCheck(Player player, String noBookMessage, String twoBooksMessage) {
+    public static boolean notHoldingOneWrittenBookCheck(@NotNull Player player, @NotNull String noBookMessage,
+                                                        @NotNull String twoBooksMessage) {
         BookHoldingState holdingState = getBookHoldingState(player);
 
         if (holdingState == BookHoldingState.NONE || holdingState == BookHoldingState.UNSIGNED_BOTH_HANDS ||
@@ -111,7 +116,8 @@ public final class InventoryHelper {
      * @param writtenBook <p>Whether to search for written or unwritten books, if it's relevant</p>
      * @return <p>The slot of the player's held book</p>
      */
-    public static ItemSlot getHeldSlotBook(Player player, boolean handMatters, boolean mainHand,
+    @NotNull
+    public static ItemSlot getHeldSlotBook(@NotNull Player player, boolean handMatters, boolean mainHand,
                                            boolean typeMatters, boolean writtenBook) {
         BookHoldingState state = getBookHoldingState(player);
         ItemStack mainHandItem = getHeldItem(player, true);
@@ -168,7 +174,8 @@ public final class InventoryHelper {
      * @param player <p>The player to check</p>
      * @return <p>The state of the player's book holding</p>
      */
-    private static BookHoldingState getBookHoldingState(Player player) {
+    @NotNull
+    private static BookHoldingState getBookHoldingState(@NotNull Player player) {
         ItemStack mainHandItem = getHeldItem(player, true);
         ItemStack offHandItem = getHeldItem(player, false);
 
@@ -205,7 +212,8 @@ public final class InventoryHelper {
      * @param mainHand <p>Whether to get information about a book in the player's main hand or off hand</p>
      * @return <p>Information about the held book</p>
      */
-    public static BookMeta getHeldBookMetadata(Player player, boolean mainHand) {
+    @Nullable
+    public static BookMeta getHeldBookMetadata(@NotNull Player player, boolean mainHand) {
         return (BookMeta) getHeldItem(player, mainHand).getItemMeta();
     }
 
@@ -216,7 +224,8 @@ public final class InventoryHelper {
      * @param mainHand <p>Whether to get the item in the player's main hand or off hand</p>
      * @return <p>The item the player is holding in the given hand</p>
      */
-    public static ItemStack getHeldItem(Player player, boolean mainHand) {
+    @NotNull
+    public static ItemStack getHeldItem(@NotNull Player player, boolean mainHand) {
         if (mainHand) {
             return player.getInventory().getItemInMainHand();
         } else {
@@ -231,7 +240,7 @@ public final class InventoryHelper {
      * @param newBook  <p>The new book the player should hold</p>
      * @param mainHand <p>Whether to replace the item in the player's main hand or off hand</p>
      */
-    public static void replaceHeldItem(Player player, ItemStack newBook, boolean mainHand) {
+    public static void replaceHeldItem(@NotNull Player player, @NotNull ItemStack newBook, boolean mainHand) {
         if (mainHand) {
             player.getInventory().setItemInMainHand(newBook);
         } else {

src/main/java/net/knarcraft/bookswithoutborders/utility/TabCompletionTypeHelper.java

@@ -1,5 +1,7 @@
 package net.knarcraft.bookswithoutborders.utility;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.util.ArrayList;
 import java.util.List;
 
@@ -16,6 +18,7 @@ public final class TabCompletionTypeHelper {
      *
      * @return <p>A list of booleans</p>
      */
+    @NotNull
     public static List<String> getBooleans() {
         List<String> booleans = new ArrayList<>();
         booleans.add("true");
@@ -30,6 +33,7 @@ public final class TabCompletionTypeHelper {
      * @param end   <p>The end number</p>
      * @return <p>A list of numbers</p>
      */
+    @NotNull
     public static List<String> getNumbers(int start, int end) {
         List<String> numbers = new ArrayList<>();
         for (int i = start; i <= end; i++) {
@@ -45,6 +49,7 @@ public final class TabCompletionTypeHelper {
      * @param end   <p>The end number</p>
      * @return <p>A list of booleans and numbers</p>
      */
+    @NotNull
     public static List<String> getBooleansAndNumbers(int start, int end) {
         List<String> booleansAndNumbers = new ArrayList<>();
         List<String> booleans = getBooleans();

src/main/resources/plugin.yml

@@ -97,6 +97,10 @@ commands:
     description: Reloads BwB's configuration file
     usage: /<command>
     permission: bookswithoutborders.reload
+  setBookshelfData:
+    description: Sets custom data for a chiseled bookshelf used when peeking at the bookshelf
+    usage: /<command> <delete/name/lore> <text> [more text]
+    permission: bookswithoutborders.editbookshelf
 permissions:
   bookswithoutborders.*:
     description: Grants all permissions
@@ -125,6 +129,7 @@ permissions:
       bookswithoutborders.setbookprice: true
       bookswithoutborders.reload: true
       bookswithoutborders.setgeneration: true
+      bookswithoutborders.editbookshelf: true
   bookswithoutborders.use:
     description: Allows player to use commands to save/load/delete in their personal directory, and peeking at bookshelves if enabled
     children:
@@ -194,3 +199,5 @@ permissions:
     description: Allows player to change the generation of a book (Original, Copy, Copy of Copy)
   bookswithoutborders.peekbookshelf:
     description: Allows player to left-click a bookshelf to see the contents of the shelf
+  bookswithoutborders.editbookshelf:
+    description: Allows player to set name/lore for bookshelves, used for peeking

src/test/java/net/knarcraft/bookswithoutborders/encryption/AESTest.java

@@ -3,6 +3,7 @@ package net.knarcraft.bookswithoutborders.encryption;
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNotSame;
 
 public class AESTest {
@@ -16,6 +17,7 @@ public class AESTest {
 
         String encrypted = aes.encryptDecryptText(plainText, password, true);
         assertNotSame(encrypted, plainText);
+        assertNotNull(encrypted);
         String decrypted = aes.encryptDecryptText(encrypted, password, false);
         assertEquals(plainText, decrypted);
     }