IdleStateHandlerInitializer.java

/*
 * Copyright 2017 the original author or authors.
 *
 * 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.takeseem.demo.netty.chapter11;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.CharsetUtil;

/**
 * 代码清单 11-7 发送心跳
 * @author <a href="https://github.com/takeseem/">杨浩</a>
 */
public class IdleStateHandlerInitializer extends ChannelInitializer<Channel> {
	private int allIdleTimeSeconds = 60;

	@Override
	protected void initChannel(Channel ch) throws Exception {
		ChannelPipeline pipeline = ch.pipeline();
		pipeline.addLast(new IdleStateHandler(0, 0, allIdleTimeSeconds), new HeartbeatHandler());
	}

	public static final class HeartbeatHandler extends ChannelInboundHandlerAdapter {
		private static final ByteBuf heartbeatSequence = Unpooled.unreleasableBuffer(Unpooled.copiedBuffer("heartbeat", CharsetUtil.ISO_8859_1));
		
		@Override
		public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
			if (evt instanceof IdleStateEvent) {
				ctx.writeAndFlush(heartbeatSequence.duplicate()).addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
			} else {
				super.userEventTriggered(ctx, evt);
			}
		}
	}
}