ThreadMode.java

/*
 * Copyright (C) 2012 Markus Junginger, greenrobot (http://greenrobot.de)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.smartandroid.sa.eventbus;

/**
 * Each event handler method has a thread mode, which determines in which thread
 * the method is to be called by EventBus. EventBus takes care of threading
 * independently from the posting thread.
 * 
 * @see EventBus#register(Object)
 * @author Markus
 */
public enum ThreadMode {
	/**
	 * Subscriber will be called in the same thread, which is posting the event.
	 * This is the default. Event delivery implies the least overhead because it
	 * avoids thread switching completely. Thus this is the recommended mode for
	 * simple tasks that are known to complete is a very short time without
	 * requiring the main thread. Event handlers using this mode must return
	 * quickly to avoid blocking the posting thread, which may be the main
	 * thread.
	 */
	PostThread,

	/**
	 * Subscriber will be called in Android's main thread (sometimes referred to
	 * as UI thread). If the posting thread is the main thread, event handler
	 * methods will be called directly. Event handlers using this mode must
	 * return quickly to avoid blocking the main thread.
	 */
	MainThread,

	/**
	 * Subscriber will be called in a background thread. If posting thread is
	 * not the main thread, event handler methods will be called directly in the
	 * posting thread. If the posting thread is the main thread, EventBus uses a
	 * single background thread, that will deliver all its events sequentially.
	 * Event handlers using this mode should try to return quickly to avoid
	 * blocking the background thread.
	 */
	BackgroundThread,

	/**
	 * Event handler methods are called in a separate thread. This is always
	 * independent from the posting thread and the main thread. Posting events
	 * never wait for event handler methods using this mode. Event handler
	 * methods should use this mode if their execution might take some time,
	 * e.g. for network access. Avoid triggering a large number of long running
	 * asynchronous handler methods at the same time to limit the number of
	 * concurrent threads. EventBus uses a thread pool to efficiently reuse
	 * threads from completed asynchronous event handler notifications.
	 */
	Async
}