Improve documentation

src/main/java/xyz/grasscutters/pltm/EventListeners.java

@@ -1,13 +1,23 @@
 package xyz.grasscutters.pltm;
 
 import emu.grasscutter.game.player.Player;
+import emu.grasscutter.server.event.EventHandler;
+import emu.grasscutter.server.event.HandlerPriority;
 import emu.grasscutter.server.event.player.PlayerJoinEvent;
 import xyz.grasscutters.pltm.objects.PluginConfig;
 
 /**
  * A class containing all event handlers.
+ * 
+ * Syntax in event handler methods are similar to CraftBukkit.
+ * To register an event handler, create a new instance of {@link EventHandler}.
+ * Pass through the event class you want to handle. (ex. `new EventHandler<>(PlayerJoinEvent.class);`)
+ * From this class, invoke {@link EventHandler#register()} to register the handler.
+ * You can change the point at which the handler method is invoked with {@link EventHandler#priority(HandlerPriority)}.
+ * You can set whether the handler method should be invoked when another plugin cancels the event with {@link EventHandler#ignore(boolean)}.
  */
 public final class EventListeners {
+    /* Saves the configuration to a local variable, reducing calls made to the plugin instance. */
     private static final PluginConfig config = PluginTemplate.getInstance().getConfiguration();
     
     /**
@@ -15,9 +25,9 @@ public final class EventListeners {
      * @param event PlayerJoinEvent.
      */
     public static void onJoin(PlayerJoinEvent event) {
-        if(!config.sendJoinMessage) return;
+        if(!config.sendJoinMessage) return; // Check if the plugin is configured to send a message when a player joins.
         
-        Player player = event.getPlayer();
-        player.dropMessage(config.joinMessage);
+        Player player = event.getPlayer(); // Get the player who joined from the event.
+        player.dropMessage(config.joinMessage); // "Drop" the player a message.
     }
 }

src/main/java/xyz/grasscutters/pltm/PluginTemplate.java

@@ -5,7 +5,9 @@ import emu.grasscutter.plugin.Plugin;
 import emu.grasscutter.server.event.EventHandler;
 import emu.grasscutter.server.event.HandlerPriority;
 import emu.grasscutter.server.event.player.PlayerJoinEvent;
-import xyz.grasscutters.pltm.objects.PluginConfig;
+
+import xyz.grasscutters.pltm.commands.*;
+import xyz.grasscutters.pltm.objects.*;
 
 import java.io.*;
 import java.util.stream.Collectors;
@@ -63,6 +65,9 @@ public final class PluginTemplate extends Plugin {
         } catch (IOException exception) {
             this.getLogger().error("Failed to create config file.", exception);
         }
+        
+        // Log a plugin status message.
+        this.getLogger().info("The example plugin has been loaded.");
     }
 
     /**
@@ -74,13 +79,20 @@ public final class PluginTemplate extends Plugin {
                 .priority(HandlerPriority.LOW)
                 .listener(EventListeners::onJoin)
                 .register();
+        
+        // Register commands.
+        this.getHandle().registerCommand(new ExampleCommand());
+
+        // Log a plugin status message.
+        this.getLogger().info("The example plugin has been enabled.");
     }
 
     /**
      * This method is called when the plugin is disabled.
      */
     @Override public void onDisable() {
-        
+        // Log a plugin status message.
+        this.getLogger().info("The example plugin has been disabled.");
     }
 
     /**

src/main/java/xyz/grasscutters/pltm/objects/PluginConfig.java

@@ -1,9 +1,28 @@
 package xyz.grasscutters.pltm.objects;
 
+import com.google.gson.Gson;
+
+import java.io.Reader;
+import java.lang.reflect.Type;
+
 /**
  * A data container for the plugin configuration.
+ * 
+ * This class is used in conjunction with {@link Gson#toJson(Object)} and {@link Gson#fromJson(Reader, Type)}.
+ * With {@link Gson}, it is possible to save and load configuration values from a JSON file.
+ * 
+ * You can set property defaults using `public Object property = (default value);`.
+ * Use {@link Gson#fromJson(Reader, Type)} to load the values set from a reader/string into a new instance of this class.
  */
 public final class PluginConfig {
-    public boolean sendJoinMessage;
-    public String joinMessage;
+    public boolean sendJoinMessage = true;
+    public String joinMessage = "Welcome to the server!";
+
+    /**
+     * When saved with {@link Gson#toJson(Object)}, it produces:
+     * {
+     *     "sendJoinMessage": true,
+     *     "joinMessage": "Welcome to the server!"
+     * }
+     */
 }