Java tutorial
/* * Copyright 2012 The Netty Project * * The Netty Project licenses this file to you 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.tcy.app.netty4; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import java.util.logging.Level; import java.util.logging.Logger; /** * Handles a client-side channel. */ public class Ne4ClientHandler extends SimpleChannelInboundHandler<Object> { private static final Logger logger = Logger.getLogger(Ne4ClientHandler.class.getName()); private final int messageSize; private ByteBuf content; private ChannelHandlerContext ctx; public Ne4ClientHandler(int messageSize) { if (messageSize <= 0) { throw new IllegalArgumentException("messageSize: " + messageSize); } this.messageSize = messageSize; } @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { this.ctx = ctx; // Initialize the message. byte[] b = "Unexpected exception from downstream.".getBytes(); content = ctx.alloc().directBuffer(1).writeBytes(b); // Send the initial messages. generateTraffic(); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { content.release(); } @Override public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { // Server is supposed to send nothing, but if it sends something, discard it. } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { // Close the connection when an exception is raised. logger.log(Level.WARNING, "Unexpected exception from downstream.", cause); ctx.close(); } long counter; private void generateTraffic() { // Flush the outbound buffer to the socket. // Once flushed, generate the same amount of traffic again. ctx.writeAndFlush(content).addListener(trafficGenerator); } private final ChannelFutureListener trafficGenerator = new ChannelFutureListener() { @Override public void operationComplete(ChannelFuture future) throws Exception { if (future.isSuccess()) { generateTraffic(); } } }; public void sendMessage(Object object) { ByteBuf buf = ctx.alloc().buffer(); buf.setByte(0, 123456); ctx.writeAndFlush(buf.duplicate().retain()).addListener(trafficGenerator); } }