Added basic Placeholders support

src/main/java/us/tastybento/bskyblock/BSkyBlock.java

@@ -44,7 +44,7 @@ public class BSkyBlock extends JavaPlugin{
             return;
         }
         
-        // Load configuration and locales if the config don't have errors.
+        // Load configuration and locales. If there are no errors, load the plugin.
         if(PluginConfig.loadPluginConfig(this)){
             playersManager = new PlayersManager(this);
             islandsManager = new IslandsManager(this);

src/main/java/us/tastybento/bskyblock/util/placeholders/PlaceholderHandler.java

@@ -0,0 +1,102 @@
+package us.tastybento.bskyblock.util.placeholders;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import org.bukkit.command.CommandSender;
+
+import us.tastybento.bskyblock.BSkyBlock;
+
+/**
+ * Handles hooks with other Placeholder APIs.
+ * 
+ * @author Poslovitch
+ * @author Tastybento
+ */
+public class PlaceholderHandler {
+    private static final String PACKAGE = "us.tastybento.bskyblock.util.placeholders.hooks.";
+    /**
+     * List of API classes in the package specified above (except the Internal one)
+     */
+    private static final String[] HOOKS = {
+            //TODO
+    };
+
+    private static List<PlaceholderInterface> apis = new ArrayList<>();
+
+    /**
+     * Register placeholders and hooks
+     * @param plugin
+     */
+    public static void register(BSkyBlock plugin){
+        // Register placeholders
+        new Placeholders(plugin);
+
+        // Load Internal Placeholder API
+        try{
+            Class<?> clazz = Class.forName(PACKAGE + "InternalPlaceholderImpl");
+            PlaceholderInterface internal = (PlaceholderInterface)clazz.newInstance();
+            apis.add(internal);
+        } catch (Exception e){
+            // Should never happen.
+            plugin.getLogger().severe("Failed to load default placeholder API");
+            e.printStackTrace();
+        }
+
+        // Load hooks
+        for(String hook : HOOKS){
+            if(plugin.getServer().getPluginManager().isPluginEnabled(hook)){
+                try{
+                    Class<?> clazz = Class.forName(PACKAGE + hook + "PlaceholderImpl");
+                    PlaceholderInterface api = (PlaceholderInterface)clazz.newInstance();
+                    if(api.register(plugin)){
+                        plugin.getLogger().info("Hooked placeholders into " + hook);
+                        apis.add(api);
+                    } else {
+                        plugin.getLogger().info("Failed to hook placeholders into " + hook);
+                    }
+                } catch (Exception e){
+                    plugin.getLogger().info("Failed to hook placeholders into " + hook);
+                    e.printStackTrace();
+                }
+            }
+        }
+    }
+
+    /**
+     * Unregister placeholder hooks
+     * @param plugin
+     */
+    public static void unregister(BSkyBlock plugin){
+        Iterator<PlaceholderInterface> it = apis.iterator();
+        while (it.hasNext()) {
+            PlaceholderInterface api = it.next();
+            api.unregister(plugin);
+            it.remove();
+        }
+    }
+
+    /**
+     * Replace placeholders in the message according to the receiver
+     * @param receiver
+     * @param message
+     * @return updated message
+     */
+    public static String replacePlaceholders(CommandSender receiver, String message){
+        if(message == null || message.isEmpty()) return "";
+
+        for(PlaceholderInterface api : apis){
+            message = api.replacePlaceholders(receiver, message);
+        }
+
+        return message;
+    }
+
+    /**
+     * @return tre if APIs are registered (including Internal), otherwise false
+     */
+    public static boolean hasHooks(){
+        return apis != null ? true : false;
+    }
+}

src/main/java/us/tastybento/bskyblock/util/placeholders/PlaceholderInterface.java

@@ -0,0 +1,40 @@
+package us.tastybento.bskyblock.util.placeholders;
+
+import org.bukkit.command.CommandSender;
+
+import us.tastybento.bskyblock.BSkyBlock;
+
+/**
+ * Simple interface for every Placeholder API.
+ * 
+ * @author Poslovitch
+ */
+public interface PlaceholderInterface {
+    
+    /**
+     * Get the name of the Placeholder API
+     * @return name of the placeholder plugin
+     */
+    String getName();
+    
+    /**
+     * Register the placeholder API
+     * @param plugin
+     * @return true if registered
+     */
+    boolean register(BSkyBlock plugin);
+    
+    /**
+     * Unregister the placeholder API
+     * @param plugin
+     */
+    void unregister(BSkyBlock plugin);
+    
+    /**
+     * Replace placeholders in the message according to the receiver
+     * @param sender
+     * @param message
+     * @return updated message
+     */
+    String replacePlaceholders(CommandSender receiver, String message);
+}

src/main/java/us/tastybento/bskyblock/util/placeholders/Placeholders.java

@@ -0,0 +1,63 @@
+package us.tastybento.bskyblock.util.placeholders;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.bukkit.command.CommandSender;
+
+import us.tastybento.bskyblock.BSkyBlock;
+
+/**
+ * Register placeholders
+ * 
+ * @author Poslovitch
+ */
+public class Placeholders {
+    private static Set<Placeholder> placeholders = new HashSet<Placeholder>();
+
+    private BSkyBlock plugin;
+
+    protected Placeholders(BSkyBlock plugin){
+        this.plugin = plugin;
+        register();
+    }
+
+    private void register(){
+        /*      PLUGIN      */
+        new Placeholder("bsb_name"){
+            @Override
+            public String onRequest(CommandSender receiver) {
+                return plugin.getDescription().getName();
+            }
+        };
+
+        new Placeholder("bsb_version") {
+
+            @Override
+            public String onRequest(CommandSender receiver) {
+                return plugin.getDescription().getVersion();
+            }
+        };
+
+        //TODO: add more placeholders
+    }
+
+    public static Set<Placeholder> getPlaceholders(){
+        return placeholders;
+    }
+
+    public abstract class Placeholder{
+        private String identifier;
+
+        protected Placeholder(String identifier){
+            this.identifier = identifier;
+            placeholders.add(this);
+        }
+
+        public String getIdentifier(){
+            return identifier;
+        }
+
+        public abstract String onRequest(CommandSender receiver);
+    }
+}

src/main/java/us/tastybento/bskyblock/util/placeholders/hooks/InternalPlaceholderImpl.java

@@ -0,0 +1,46 @@
+package us.tastybento.bskyblock.util.placeholders.hooks;
+
+import java.util.regex.Pattern;
+
+import org.bukkit.command.CommandSender;
+
+import us.tastybento.bskyblock.BSkyBlock;
+import us.tastybento.bskyblock.util.placeholders.PlaceholderInterface;
+import us.tastybento.bskyblock.util.placeholders.Placeholders;
+import us.tastybento.bskyblock.util.placeholders.Placeholders.Placeholder;
+
+/**
+ * Built-in placeholder API
+ * 
+ * @author Poslovitch
+ */
+public class InternalPlaceholderImpl implements PlaceholderInterface{
+
+    @Override
+    public String getName() {
+        return "Internal";
+    }
+
+    @Override
+    public boolean register(BSkyBlock plugin) {
+        return true;
+    }
+
+    @Override
+    public void unregister(BSkyBlock plugin) {
+        // Useless : it would disable the placeholders.
+    }
+
+    @Override
+    public String replacePlaceholders(CommandSender receiver, String message) {
+        if(message == null || message.isEmpty()) return "";
+
+        for(Placeholder placeholder : Placeholders.getPlaceholders()){
+            String identifier = "{" + placeholder.getIdentifier() + "}";
+            message = message.replaceAll(Pattern.quote(identifier), placeholder.onRequest(receiver));
+        }
+
+        return message;
+    }
+
+}