Extracts some functions for finding and replacing books to InventoryHelper

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

@@ -16,6 +16,7 @@ import java.util.Objects;
 import net.knarcraft.bookswithoutborders.utility.BookFormatter;
 import net.knarcraft.bookswithoutborders.utility.EncryptionHelper;
 import net.knarcraft.bookswithoutborders.utility.FileHelper;
+import net.knarcraft.bookswithoutborders.utility.InventoryHelper;
 import net.milkbowl.vault.economy.Economy;
 import org.bukkit.ChatColor;
 import org.bukkit.Material;
@@ -558,46 +559,8 @@ public class BooksWithoutBorders extends JavaPlugin {
                         return commandUnSign(player);
                     case "copy":
                         return commandCopy(player, args);
-                }
+                    case "encrypt":
-
+                        return commandEncrypt(player, args);
-                if (args[0].equalsIgnoreCase("encrypt")) {
-                    if (!sender.hasPermission("bookswithoutborders.encrypt")) {
-                        sendErrorMessage(sender, " You don't have permission to use this command!");
-                        return false;
-                    }
-
-                    if (!(((Player) sender).getItemInHand().getType() == Material.WRITTEN_BOOK)) {
-                        sendErrorMessage(sender, "You must be holding a written book to encrypt it!");
-                        return false;
-                    }
-
-                    if (args.length < 2) {
-                        sendErrorMessage(sender, "You must specify a key to encrypt a book!");
-                        return false;
-                    }
-                    if (args.length > 3) {
-                        sendErrorMessage(sender, "Too many command options specified!");
-                        return false;
-                    }
-
-                    if (!((BookMeta) ((Player) sender).getItemInHand().getItemMeta()).hasPages()) {
-                        sendErrorMessage(sender, "Book must have contents to encrypt!");
-                        return false;
-                    }
-
-                    ItemStack eBook;
-
-                    if (args.length == 3) {
-                        eBook = encryptBook((Player) sender, true, args[1], EncryptionStyle.getFromString(args[2]), "");
-                    } else {
-                        eBook = encryptBook((Player) sender, true, args[1], EncryptionStyle.SUBSTITUTION, "");
-                    }
-
-                    if (eBook != null) {
-                        ((Player) sender).setItemInHand(eBook);
-                        return true;
-                    } else
-                        return false;
                 }
 
                 if (args[0].equalsIgnoreCase("groupEncrypt")) {
@@ -973,6 +936,48 @@ public class BooksWithoutBorders extends JavaPlugin {
         return false;
     }
 
+    protected boolean commandEncrypt(Player player, String[] args) {
+        if (!player.hasPermission("bookswithoutborders.encrypt")) {
+            sendErrorMessage(player, " You don't have permission to use this command!");
+            return false;
+        }
+
+        if (InventoryHelper.notHoldingOneBookCheck(player, "You must be holding a written book to encrypt it!",
+                "You cannot encrypt two books at once!")) {
+            return false;
+        }
+
+        if (args.length < 2) {
+            sendErrorMessage(player, "You must specify a key to encrypt a book!");
+            return false;
+        }
+        if (args.length > 3) {
+            sendErrorMessage(player, "Too many command options specified!");
+            return false;
+        }
+
+        ItemStack heldBook = InventoryHelper.getHeldBook(player);
+
+        if (!((BookMeta) Objects.requireNonNull(heldBook.getItemMeta())).hasPages()) {
+            sendErrorMessage(player, "Book must have contents to encrypt!");
+            return false;
+        }
+
+        ItemStack encryptedBook;
+
+        if (args.length == 3) {
+            encryptedBook = encryptBook(player, true, args[1], EncryptionStyle.getFromString(args[2]), "");
+        } else {
+            encryptedBook = encryptBook(player, true, args[1], EncryptionStyle.SUBSTITUTION, "");
+        }
+
+        if (encryptedBook != null) {
+            InventoryHelper.setHeldBook(player, encryptedBook);
+            return true;
+        } else
+            return false;
+    }
+
     /**
      * Executes the copy command
      * @param player <p>The player which sent the command</p>
@@ -985,15 +990,8 @@ public class BooksWithoutBorders extends JavaPlugin {
             return false;
         }
 
-        BookHoldingState holdingState = holdingBook(player);
+        if (InventoryHelper.notHoldingOneBookCheck(player, "You must be holding a written book to copy it!",
-
+                "You cannot copy two books at once!")) {
-        if (holdingState == BookHoldingState.NONE) {
-            sendErrorMessage(player, "You must be holding a written book to copy it!");
-            return false;
-        }
-
-        if (holdingState == BookHoldingState.BOTH_HANDS) {
-            sendErrorMessage(player, "You cannot copy two books at once!");
             return false;
         }
 
@@ -1002,12 +1000,7 @@ public class BooksWithoutBorders extends JavaPlugin {
             return false;
         }
 
-        ItemStack heldBook;
+        ItemStack heldBook = InventoryHelper.getHeldBook(player);
-        if (holdingState == BookHoldingState.MAIN_HAND) {
-            heldBook = player.getInventory().getItemInMainHand();
-        } else {
-            heldBook = player.getInventory().getItemInOffHand();
-        }
 
         try {
             if (Integer.parseInt(args[1]) > 0) {
@@ -1048,43 +1041,17 @@ public class BooksWithoutBorders extends JavaPlugin {
             return false;
         }
 
-        BookHoldingState holdingState = holdingBook(player);
+        if (InventoryHelper.notHoldingOneBookCheck(player, "You must be holding a written book to un-sign it!",
-
+                "You cannot un-sign two books at once. Please un-equip one of the books you're holding!")) {
-        if (holdingState == BookHoldingState.NONE) {
-            sendErrorMessage(player, "You must be holding a written book to un-sign it!");
             return false;
         }
 
         //Find which hand the player is using to hold the book. If holding one in each, throw an error
-        if (holdingState == BookHoldingState.BOTH_HANDS) {
+        BookHoldingState holdingState = InventoryHelper.getHoldingBookState(player);
-            sendErrorMessage(player, "You cannot un-sign two books at once. Please un-equip one " +
+        unSignHeldBook(player, holdingState == BookHoldingState.MAIN_HAND);
-                    "of the books you're holding!");
-        } else {
-            unSignHeldBook(player, holdingState == BookHoldingState.MAIN_HAND);
-        }
         return true;
     }
 
-    /**
-     * Gets the state of which hands of the player contains a book
-     * @param player <p>The player possibly holding a book</p>
-     * @return <p>The state of the player's book holding</p>
-     */
-    protected BookHoldingState holdingBook(Player player) {
-        boolean hasBookInMainHand = player.getInventory().getItemInMainHand().getType() == Material.WRITTEN_BOOK;
-        boolean hasBookInOffHand = player.getInventory().getItemInOffHand().getType() == Material.WRITTEN_BOOK;
-
-        if (hasBookInMainHand && hasBookInOffHand) {
-            return BookHoldingState.BOTH_HANDS;
-        } else if (hasBookInMainHand) {
-            return BookHoldingState.MAIN_HAND;
-        } else if (hasBookInOffHand) {
-            return BookHoldingState.OFF_HAND;
-        } else {
-            return BookHoldingState.NONE;
-        }
-    }
-
     /**
      * Executes the delete command
      * @param player <p>The player which sent the command</p>
@@ -1695,7 +1662,7 @@ public class BooksWithoutBorders extends JavaPlugin {
         //converts user supplied key into integer form
         String integerKey = EncryptionHelper.getNumberKeyFromStringKey(key);
 
-        BookMeta book = getHeldBookMetadata(player, mainHand);
+        BookMeta book = InventoryHelper.getHeldBookMetadata(player, mainHand);
 
         if (!book.hasPages()) {
             sendErrorMessage(player, "Book is empty!");
@@ -1741,11 +1708,7 @@ public class BooksWithoutBorders extends JavaPlugin {
         encryptedBook.setItemMeta(book);
 
         //Update item amount
-        if (mainHand) {
+        encryptedBook.setAmount(InventoryHelper.getHeldBook(player).getAmount());
-            encryptedBook.setAmount(player.getInventory().getItemInMainHand().getAmount());
-        } else {
-            encryptedBook.setAmount(player.getInventory().getItemInOffHand().getAmount());
-        }
         //Set new item metadata
         encryptedBook.setItemMeta(newMetadata);
 
@@ -1847,43 +1810,13 @@ public class BooksWithoutBorders extends JavaPlugin {
      */
     protected void unSignHeldBook(Player player, boolean mainHand) {
         //Get the old book
-        BookMeta oldBook = getHeldBookMetadata(player, mainHand);
+        BookMeta oldBook = InventoryHelper.getHeldBookMetadata(player, mainHand);
 
         //UnSign the book
         ItemStack newBook = new ItemStack(Material.WRITABLE_BOOK);
         newBook.setItemMeta(oldBook);
 
-        replaceHeldBook(player, newBook, mainHand);
+        InventoryHelper.replaceHeldBook(player, newBook, mainHand);
-    }
-
-    /**
-     * Gets metadata about the player's held book
-     *
-     * @param player   <p>The player holding the book</p>
-     * @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>
-     */
-    private BookMeta getHeldBookMetadata(Player player, boolean mainHand) {
-        if (mainHand) {
-            return (BookMeta) player.getInventory().getItemInMainHand().getItemMeta();
-        } else {
-            return (BookMeta) player.getInventory().getItemInOffHand().getItemMeta();
-        }
-    }
-
-    /**
-     * Replaces the player's held item
-     *
-     * @param player   <p>The player to replace the item for</p>
-     * @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>
-     */
-    private void replaceHeldBook(Player player, ItemStack newBook, boolean mainHand) {
-        if (mainHand) {
-            player.getInventory().setItemInMainHand(newBook);
-        } else {
-            player.getInventory().setItemInOffHand(newBook);
-        }
     }
 
     /**

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

@@ -0,0 +1,123 @@
+package net.knarcraft.bookswithoutborders.utility;
+
+import net.knarcraft.bookswithoutborders.BookHoldingState;
+import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import org.bukkit.Material;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.BookMeta;
+
+public class InventoryHelper {
+
+    /**
+     * Gets the book the holder is playing
+     * @param player <p>The player holding the book</p>
+     * @return <p>The book the player is holding</p>
+     */
+    public static ItemStack getHeldBook(Player player) {
+        BookHoldingState holdingState = getHoldingBookState(player);
+        ItemStack heldBook;
+        if (holdingState == BookHoldingState.MAIN_HAND) {
+            heldBook = getHeldBook(player, true);
+        } else if (holdingState == BookHoldingState.OFF_HAND) {
+            heldBook = getHeldBook(player, false);
+        } else {
+            throw new IllegalArgumentException("The player is not holding exactly one book.");
+        }
+        return heldBook;
+    }
+
+    /**
+     * Replaces the book the player is holding
+     * @param player <p>The player holding the book</p>
+     * @param newBook <p>The new book the player should hold</p>
+     */
+    public static void setHeldBook(Player player, ItemStack newBook) {
+        BookHoldingState holdingState = getHoldingBookState(player);
+        replaceHeldBook(player, newBook, holdingState == BookHoldingState.MAIN_HAND);
+    }
+
+    /**
+     * Performs checks to validate that a player contains exactly one book
+     * @param player <p>The player to validate</p>
+     * @param noBookMessage <p>The message to display if the player is not holding a book</p>
+     * @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 notHoldingOneBookCheck(Player player, String noBookMessage, String twoBooksMessage) {
+        BookHoldingState holdingState = getHoldingBookState(player);
+
+        if (holdingState == BookHoldingState.NONE) {
+            BooksWithoutBorders.sendErrorMessage(player, noBookMessage);
+            return true;
+        }
+
+        if (holdingState == BookHoldingState.BOTH_HANDS) {
+            BooksWithoutBorders.sendErrorMessage(player, twoBooksMessage);
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Gets the state of which hands of the player contains a book
+     * @param player <p>The player possibly holding a book</p>
+     * @return <p>The state of the player's book holding</p>
+     */
+    public static BookHoldingState getHoldingBookState(Player player) {
+        boolean hasBookInMainHand = player.getInventory().getItemInMainHand().getType() == Material.WRITTEN_BOOK;
+        boolean hasBookInOffHand = player.getInventory().getItemInOffHand().getType() == Material.WRITTEN_BOOK;
+
+        if (hasBookInMainHand && hasBookInOffHand) {
+            return BookHoldingState.BOTH_HANDS;
+        } else if (hasBookInMainHand) {
+            return BookHoldingState.MAIN_HAND;
+        } else if (hasBookInOffHand) {
+            return BookHoldingState.OFF_HAND;
+        } else {
+            return BookHoldingState.NONE;
+        }
+    }
+
+    /**
+     * Gets metadata about the player's held book
+     *
+     * @param player   <p>The player holding the book</p>
+     * @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) {
+        return (BookMeta) getHeldBook(player, mainHand).getItemMeta();
+    }
+
+    /**
+     * Gets the item the player is holding
+     * @param player <p>The player to get from</p>
+     * @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 getHeldBook(Player player, boolean mainHand) {
+        if (mainHand) {
+            return player.getInventory().getItemInMainHand();
+        } else {
+            return player.getInventory().getItemInOffHand();
+        }
+    }
+
+    /**
+     * Replaces the player's held item
+     *
+     * @param player   <p>The player to replace the item for</p>
+     * @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 replaceHeldBook(Player player, ItemStack newBook, boolean mainHand) {
+        if (mainHand) {
+            player.getInventory().setItemInMainHand(newBook);
+        } else {
+            player.getInventory().setItemInOffHand(newBook);
+        }
+    }
+
+}