Java tutorial
/* * Copyright 2013-2018 Lilinfeng. * * 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.heelenyc.im.client.handler; import io.netty.channel.ChannelHandlerAdapter; import io.netty.channel.ChannelHandlerContext; import java.util.concurrent.ScheduledFuture; import java.util.concurrent.TimeUnit; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import com.heelenyc.im.common.Constans; import com.heelenyc.im.common.entity.Header; import com.heelenyc.im.common.entity.Message; import com.heelenyc.im.common.entity.MessageType; public class ClientHeartBeatReqHandler extends ChannelHandlerAdapter { private Log logger = LogFactory.getLog(this.getClass()); private volatile ScheduledFuture<?> heartBeat; @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { Message message = (Message) msg; // ????? if (message.getHeader() != null && message.getHeader().getType() == MessageType.LOGIN_RESP.value()) { heartBeat = ctx.executor().scheduleAtFixedRate(new ClientHeartBeatReqHandler.HeartBeatTask(ctx), 0, Constans.HEARTBEAT_PERIOD_INMS, TimeUnit.MILLISECONDS); } else if (message.getHeader() != null && message.getHeader().getType() == MessageType.HEARTBEAT_RESP.value()) { logger.info("Client receive server heart beat message : ---> " + message); } else ctx.fireChannelRead(msg); } private class HeartBeatTask implements Runnable { private final ChannelHandlerContext ctx; public HeartBeatTask(final ChannelHandlerContext ctx) { this.ctx = ctx; } @Override public void run() { Message heatBeat = buildHeatBeat(); logger.info("Client send heart beat messsage to server : ---> " + heatBeat); ctx.writeAndFlush(heatBeat); } private Message buildHeatBeat() { Message message = new Message(); Header header = new Header(); header.setType(MessageType.HEARTBEAT_REQ.value()); message.setHeader(header); return message; } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); if (heartBeat != null) { heartBeat.cancel(true); heartBeat = null; } ctx.fireExceptionCaught(cause); } }