Adds clearBook command #7 and improves README

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

@@ -1,6 +1,7 @@
 package net.knarcraft.bookswithoutborders;
 
 import net.knarcraft.bookswithoutborders.command.CommandBooksWithoutBorders;
+import net.knarcraft.bookswithoutborders.command.CommandClear;
 import net.knarcraft.bookswithoutborders.command.CommandCopy;
 import net.knarcraft.bookswithoutborders.command.CommandDecrypt;
 import net.knarcraft.bookswithoutborders.command.CommandDelete;
@@ -173,6 +174,7 @@ public class BooksWithoutBorders extends JavaPlugin {
         registerCommand("reload", new CommandReload());
         registerCommand("formatBook", new CommandFormat());
         registerCommand("setBookGeneration", new CommandSetGeneration());
+        registerCommand("clearBook", new CommandClear());
     }
 
     /**

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

@@ -0,0 +1,48 @@
+package net.knarcraft.bookswithoutborders.command;
+
+import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
+import net.knarcraft.bookswithoutborders.utility.InventoryHelper;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabExecutor;
+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;
+
+/**
+ * Command executor for the clear command
+ */
+public class CommandClear implements TabExecutor {
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                             @NotNull String[] args) {
+        if (!(sender instanceof Player player)) {
+            BooksWithoutBorders.sendErrorMessage(sender, "This command can only be used by a player!");
+            return false;
+        }
+
+        InventoryHelper.notHoldingOneWritableBookCheck(player, "You must be holding a writable book to copy it!",
+                "You cannot copy two books at once!");
+
+        //Clear the player's held book
+        ItemStack heldBook = InventoryHelper.getHeldBook(player, true);
+        BookMeta bookMeta = (BookMeta) heldBook;
+        bookMeta.setPages("");
+        heldBook.setItemMeta(bookMeta);
+        return true;
+    }
+
+    @Nullable
+    @Override
+    public List<String> onTabComplete(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
+                                      @NotNull String[] args) {
+        return new ArrayList<>();
+    }
+
+}

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

@@ -103,7 +103,7 @@ public final class EconomyHelper {
     private static boolean takeWritableBookPayment(Player player, int itemCost) {
         List<ItemStack> books = getPlayersEmptyBooks(player);
         if (countItems(books) < itemCost) {
-            BooksWithoutBorders.sendErrorMessage(player, itemCost + " " + Material.WRITABLE_BOOK +
+            BooksWithoutBorders.sendErrorMessage(player, itemCost + " empty " + Material.WRITABLE_BOOK +
                     "(s) are required for this command!");
             return false;
         } else {

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

@@ -51,6 +51,31 @@ public final class InventoryHelper {
         }
     }
 
+    /**
+     * Performs checks to validate that a player contains exactly one unwritten 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 notHoldingOneWritableBookCheck(Player player, String noBookMessage, String twoBooksMessage) {
+        BookHoldingState holdingState = getBookHoldingState(player);
+
+        if (holdingState == BookHoldingState.NONE || holdingState == BookHoldingState.SIGNED_BOTH_HANDS ||
+                holdingState == BookHoldingState.SIGNED_MAIN_HAND || holdingState == BookHoldingState.SIGNED_OFF_HAND) {
+            BooksWithoutBorders.sendErrorMessage(player, noBookMessage);
+            return true;
+        }
+
+        if (holdingState == BookHoldingState.UNSIGNED_BOTH_HANDS) {
+            BooksWithoutBorders.sendErrorMessage(player, twoBooksMessage);
+            return true;
+        }
+
+        return false;
+    }
+
     /**
      * Performs checks to validate that a player contains exactly one written book
      *

src/main/resources/plugin.yml

@@ -45,6 +45,10 @@ commands:
     description: Copies the book the player is holding
     usage: /<command> <# of copies>
     permission: bookswithoutborders.copy
+  clearbook:
+    description: Removes all text from the book the player is holding
+    usage: /<command>
+    permission: bookswithoutborders.clear
   unsignbook:
     description: Un-signs the book the player is holding
     usage: /<command>
@@ -130,6 +134,7 @@ permissions:
   bookswithoutborders.alterbooks:
     description: Allows player to change books' data such as lore/title/author/generation/formatting and unsigning books
     children:
+      bookswithoutborders.clear: true
       bookswithoutborders.unsign: true
       bookswithoutborders.settitle: true
       bookswithoutborders.setauthor: true
@@ -145,9 +150,11 @@ permissions:
   bookswithoutborders.delete:
     description: Allows player to delete books from their personal directory
   bookswithoutborders.unsign:
-    description: Allows player to use unsign command
+    description: Allows player to use the unsign command
   bookswithoutborders.copy:
-    description: Allows player to use copy command
+    description: Allows player to use the copy command
+  bookswithoutborders.clear:
+    description: Allows player to use the clear command
   bookswithoutborders.loadpublic:
     description: Allows player to load from the public directory
   bookswithoutborders.savepublic: