Added methods to unregister placeholders in PlaceholdersManager

#592

src/main/java/world/bentobox/bentobox/api/placeholders/placeholderapi/BasicPlaceholderExpansion.java

@@ -7,11 +7,16 @@ import java.util.Map;
 import org.bukkit.entity.Player;
 
 import me.clip.placeholderapi.expansion.PlaceholderExpansion;
+import org.eclipse.jdt.annotation.NonNull;
 import world.bentobox.bentobox.api.placeholders.PlaceholderReplacer;
 import world.bentobox.bentobox.api.user.User;
 
+/**
+ * @author Poslovitch
+ */
 abstract class BasicPlaceholderExpansion extends PlaceholderExpansion {
-    private Map<String, PlaceholderReplacer> placeholders;
+    @NonNull
+    private Map<@NonNull String, @NonNull PlaceholderReplacer> placeholders;
 
     BasicPlaceholderExpansion() {
         this.placeholders = new HashMap<>();
@@ -22,10 +27,19 @@ abstract class BasicPlaceholderExpansion extends PlaceholderExpansion {
         return getName().toLowerCase(Locale.ENGLISH);
     }
 
-    public void registerPlaceholder(String placeholder, PlaceholderReplacer replacer) {
+    public void registerPlaceholder(@NonNull String placeholder, @NonNull PlaceholderReplacer replacer) {
         placeholders.putIfAbsent(placeholder, replacer);
     }
 
+    /**
+     * Unregisters a placeholder from the expansion.
+     * @param placeholder the placeholder to unregister.
+     * @since 1.4.0
+     */
+    public void unregisterPlaceholder(@NonNull String placeholder) {
+        placeholders.remove(placeholder);
+    }
+
     @Override
     public String onPlaceholderRequest(Player p, String placeholder) {
         User user = User.getInstance(p);

src/main/java/world/bentobox/bentobox/hooks/PlaceholderAPIHook.java

@@ -3,6 +3,8 @@ package world.bentobox.bentobox.hooks;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.addons.Addon;
 import world.bentobox.bentobox.api.hooks.Hook;
@@ -41,16 +43,33 @@ public class PlaceholderAPIHook extends Hook {
         return "could not register BentoBox's expansion";
     }
 
+    /**
+     * @deprecated As of 1.4.0, renamed to {@link #registerPlaceholder(String, PlaceholderReplacer)}.
+     */
+    @Deprecated
     public void registerBentoBoxPlaceholder(String placeholder, PlaceholderReplacer replacer) {
+        registerPlaceholder(placeholder, replacer);
+    }
+
+    /**
+     * Registers this placeholder into BentoBox's PlaceholderAPI expansion.
+     * @param placeholder the placeholder to register, not null
+     * @param replacer its replacement, not null
+     * @since 1.4.0
+     */
+    public void registerPlaceholder(@NonNull String placeholder, @NonNull PlaceholderReplacer replacer) {
         bentoboxExpansion.registerPlaceholder(placeholder, replacer);
     }
 
-    public void registerAddonPlaceholder(Addon addon, String placeholder, PlaceholderReplacer replacer) {
+    /**
-        // If addon is null, then register the placeholder in BentoBox's expansion.
+     * Registers this placeholder into this addon's PlaceholderAPI expansion.
-        if (addon == null) {
+     * It will register the expansion if it previously did not exist.
-            registerBentoBoxPlaceholder(placeholder, replacer);
+     * @param addon the addon, not null
-        }
+     * @param placeholder the placeholder to register, not null
-
+     * @param replacer its replacement, not null
+     * @since 1.4.0
+     */
+    public void registerPlaceholder(@NonNull Addon addon, @NonNull String placeholder, @NonNull PlaceholderReplacer replacer) {
         // Check if the addon expansion does not exist
         if (!addonsExpansions.containsKey(addon)) {
             AddonPlaceholderExpansion addonPlaceholderExpansion = new AddonPlaceholderExpansion(addon);
@@ -60,4 +79,33 @@ public class PlaceholderAPIHook extends Hook {
 
         addonsExpansions.get(addon).registerPlaceholder(placeholder, replacer);
     }
+
+    /**
+     * Unregisters this placeholder from the BentoBox PlaceholderAPI expansion.
+     * @param placeholder the placeholder to unregister, not null
+     * @since 1.4.0
+     */
+    public void unregisterPlaceholder(@NonNull String placeholder) {
+        bentoboxExpansion.unregisterPlaceholder(placeholder);
+    }
+
+    /**
+     * Unregister this placeholder from this addon's PlaceholderAPI expansion.
+     * @param addon the addon, not null
+     * @param placeholder the placeholder to unregister, not null
+     * @since 1.4.0
+     */
+    public void unregisterPlaceholder(@NonNull Addon addon, @NonNull String placeholder) {
+        if (addonsExpansions.containsKey(addon)) {
+            addonsExpansions.get(addon).unregisterPlaceholder(placeholder);
+        }
+    }
+
+    /**
+     * @deprecated As of 1.4.0, renamed to {@link #registerPlaceholder(Addon, String, PlaceholderReplacer)}.
+     */
+    @Deprecated
+    public void registerAddonPlaceholder(Addon addon, String placeholder, PlaceholderReplacer replacer) {
+        registerPlaceholder(addon, placeholder, replacer);
+    }
 }

src/main/java/world/bentobox/bentobox/managers/PlaceholdersManager.java

@@ -1,10 +1,14 @@
 package world.bentobox.bentobox.managers;
 
+import com.mongodb.lang.NonNull;
+import com.mongodb.lang.Nullable;
 import world.bentobox.bentobox.BentoBox;
 import world.bentobox.bentobox.api.addons.Addon;
 import world.bentobox.bentobox.api.placeholders.PlaceholderReplacer;
 import world.bentobox.bentobox.hooks.PlaceholderAPIHook;
 
+import java.util.Optional;
+
 /**
  * Manages placeholder integration.
  *
@@ -19,26 +23,66 @@ public class PlaceholdersManager {
     }
 
     /**
-     * Registers the placeholder on the behalf on BentoBox.
+     * Registers this placeholder on the behalf of BentoBox.
-     * @param placeholder the placeholder to register. It will be appended with {@code "bentobox_"} by the placeholder plugin.
+     * @param placeholder the placeholder to register, not null.
-     * @param replacer the expression that will return a {@code String} when executed, which will replace the placeholder.
+     *                    It will be appended with {@code "bentobox_"} by the placeholder plugin.
+     * @param replacer the expression that will return a {@code String} when executed, which will be this placeholder's replacement.
      */
-    public void registerPlaceholder(String placeholder, PlaceholderReplacer replacer) {
+    public void registerPlaceholder(@NonNull String placeholder, @NonNull PlaceholderReplacer replacer) {
         // Register it in PlaceholderAPI
-        plugin.getHooks().getHook("PlaceholderAPI").ifPresent(hook -> ((PlaceholderAPIHook) hook).registerBentoBoxPlaceholder(placeholder, replacer));
+        getPlaceholderAPIHook().ifPresent(hook -> hook.registerPlaceholder(placeholder, replacer));
     }
 
     /**
-     * Registers the placeholder on the behalf of the specified addon.
+     * Registers this placeholder on the behalf of the specified addon.
-     * @param placeholder the placeholder to register. It will be appended with the addon's name by the placeholder plugin.
+     * @param addon the addon to register this placeholder on its behalf.
+     *              If null, the placeholder will be registered using {@link #registerPlaceholder(String, PlaceholderReplacer)}.
+     * @param placeholder the placeholder to register, not null.
+     *                    It will be appended with the addon's name by the placeholder plugin.
      * @param replacer the expression that will return a {@code String} when executed, which will replace the placeholder.
      */
-    public void registerPlaceholder(Addon addon, String placeholder, PlaceholderReplacer replacer) {
+    public void registerPlaceholder(@Nullable Addon addon, @NonNull String placeholder, @NonNull PlaceholderReplacer replacer) {
         if (addon == null) {
             registerPlaceholder(placeholder, replacer);
             return;
         }
         // Register it in PlaceholderAPI
-        plugin.getHooks().getHook("PlaceholderAPI").ifPresent(hook -> ((PlaceholderAPIHook) hook).registerAddonPlaceholder(addon, placeholder, replacer));
+        getPlaceholderAPIHook().ifPresent(hook -> hook.registerPlaceholder(addon, placeholder, replacer));
+    }
+
+    /**
+     * Unregisters this placeholder on the behalf of BentoBox.
+     * Note that if the placeholder you are trying to unregister has been registered by an addon, you should use {@link #unregisterPlaceholder(Addon, String)} instead.
+     * @param placeholder the placeholder to unregister, not null.
+     * @since 1.4.0
+     */
+    public void unregisterPlaceholder(@NonNull String placeholder) {
+        // Unregister it from PlaceholderAPI
+        getPlaceholderAPIHook().ifPresent(hook -> hook.unregisterPlaceholder(placeholder));
+    }
+
+    /**
+     * Unregisters this placeholder on the behalf of the specified addon.
+     * @param addon the addon that originally registered this placeholder.
+     *              If null, this placeholder will be unregistered using {@link #unregisterPlaceholder(String)}.
+     * @param placeholder the placeholder to unregister, not null.
+     * @since 1.4.0
+     */
+    public void unregisterPlaceholder(@Nullable Addon addon, @NonNull String placeholder) {
+        if (addon == null) {
+            unregisterPlaceholder(placeholder);
+            return;
+        }
+        // Unregister it from PlaceholderAPI
+        getPlaceholderAPIHook().ifPresent(hook -> hook.unregisterPlaceholder(addon, placeholder));
+    }
+
+    /**
+     * Returns an Optional containing the PlaceholderAPIHook instance, or an empty Optional otherwise.
+     * @return Optional containing the PlaceholderAPIHook instance or an empty Optional otherwise.
+     * @since 1.4.0
+     */
+    private Optional<PlaceholderAPIHook> getPlaceholderAPIHook() {
+        return plugin.getHooks().getHook("PlaceholderAPI").map(hook -> (PlaceholderAPIHook) hook);
     }
 }