docs: add javadoc for event bus

api/src/main/java/org/allaymc/api/eventbus/EventBus.java

@@ -9,14 +9,36 @@
 public interface EventBus {
     ApiInstanceHolder<Factory> FACTORY = ApiInstanceHolder.create();
 
+    /**
+     * Create a new event bus.
+     *
+     * @return a new event bus.
+     */
     static EventBus create() {
         return FACTORY.get().create();
     }
 
+    /**
+     * Register a listener.
+     *
+     * @param listener the listener to register.
+     */
     void registerListener(Object listener);
 
+    /**
+     * Unregister a listener.
+     *
+     * @param listener the listener to unregister.
+     */
     void unregisterListener(Object listener);
 
+    /**
+     * Call an event.
+     *
+     * @param event the event to call.
+     * @return the event.
+     * @param <E> the type of the event.
+     */
     <E extends Event> E callEvent(E event);
 
     interface Factory {

api/src/main/java/org/allaymc/api/eventbus/EventHandler.java

@@ -6,12 +6,24 @@
 import java.lang.annotation.Target;
 
 /**
+ * An annotation to mark a method as an event handler.
+ *
  * @author daoge_cmd
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)
 public @interface EventHandler {
+    /**
+     * Whether the event handler should be called asynchronously.
+     *
+     * @return {@code true} if the event handler should be called asynchronously, otherwise {@code false}
+     */
     boolean async() default false;
 
+    /**
+     * The priority of the event handler.
+     *
+     * @return the priority of the event handler
+     */
     int priority() default 0;
 }

api/src/main/java/org/allaymc/api/eventbus/event/CancellableEvent.java

@@ -1,13 +1,30 @@
 package org.allaymc.api.eventbus.event;
 
 /**
+ * An interface to represent a cancellable event.
+ * <p>
+ * Event that implements this interface is cancelled.
+ *
  * @author daoge_cmd
  */
 public interface CancellableEvent {
+    /**
+     * Check whether the event is cancelled.
+     *
+     * @return {@code true} if the event is cancelled, otherwise {@code false}.
+     */
     boolean isCancelled();
 
+    /**
+     * Set the event to be cancelled or not.
+     *
+     * @param value {@code true} if the event is cancelled, otherwise {@code false}.
+     */
     void setCancelled(boolean value);
 
+    /**
+     * Cancel the event.
+     */
     default void cancel() {
         setCancelled(true);
     }

api/src/main/java/org/allaymc/api/eventbus/event/Event.java

@@ -6,20 +6,36 @@
 import org.allaymc.api.server.Server;
 
 /**
+ * An abstract class to represent an event.
+ *
  * @author daoge_cmd
  */
 public abstract class Event {
     @Getter
     private boolean cancelled = false;
 
+    /**
+     * Call the event with the default event bus.
+     */
     public void call() {
         call(Server.getInstance().getEventBus());
     }
 
+    /**
+     * Call the event with the specified event bus.
+     *
+     * @param eventBus the event bus to call the event.
+     */
     public void call(EventBus eventBus) {
         eventBus.callEvent(this);
     }
 
+    /**
+     * Cancel the event.
+     *
+     * @param value {@code true} if the event is cancelled, otherwise {@code false}.
+     * @throws EventException if the event is not cancellable.
+     */
     public void setCancelled(boolean value) {
         if (!(this instanceof CancellableEvent)) {
             throw new EventException("Event is not Cancellable");