128 lines
4.1 KiB
Java
128 lines
4.1 KiB
Java
/*
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* Copyright 2011 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.example.factorial;
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import java.math.BigInteger;
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import java.util.concurrent.BlockingQueue;
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import java.util.concurrent.LinkedBlockingQueue;
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import java.util.logging.Level;
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import java.util.logging.Logger;
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import io.netty.channel.Channel;
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import io.netty.channel.ChannelEvent;
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import io.netty.channel.ChannelFuture;
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import io.netty.channel.ChannelFutureListener;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelStateEvent;
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import io.netty.channel.ExceptionEvent;
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import io.netty.channel.MessageEvent;
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import io.netty.channel.SimpleChannelUpstreamHandler;
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/**
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* Handler for a client-side channel. This handler maintains stateful
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* information which is specific to a certain channel using member variables.
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* Therefore, an instance of this handler can cover only one channel. You have
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* to create a new handler instance whenever you create a new channel and insert
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* this handler to avoid a race condition.
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*/
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public class FactorialClientHandler extends SimpleChannelUpstreamHandler {
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private static final Logger logger = Logger.getLogger(
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FactorialClientHandler.class.getName());
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// Stateful properties
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private int i = 1;
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private int receivedMessages;
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private final int count;
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final BlockingQueue<BigInteger> answer = new LinkedBlockingQueue<BigInteger>();
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public FactorialClientHandler(int count) {
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this.count = count;
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}
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public BigInteger getFactorial() {
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boolean interrupted = false;
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for (;;) {
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try {
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BigInteger factorial = answer.take();
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if (interrupted) {
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Thread.currentThread().interrupt();
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}
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return factorial;
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} catch (InterruptedException e) {
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interrupted = true;
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}
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}
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}
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@Override
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public void handleUpstream(
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ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
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if (e instanceof ChannelStateEvent) {
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logger.info(e.toString());
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}
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super.handleUpstream(ctx, e);
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}
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@Override
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public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
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sendNumbers(e);
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}
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@Override
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public void channelInterestChanged(ChannelHandlerContext ctx, ChannelStateEvent e) {
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sendNumbers(e);
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}
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@Override
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public void messageReceived(
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ChannelHandlerContext ctx, final MessageEvent e) {
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receivedMessages ++;
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if (receivedMessages == count) {
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// Offer the answer after closing the connection.
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e.getChannel().close().addListener(new ChannelFutureListener() {
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@Override
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public void operationComplete(ChannelFuture future) {
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boolean offered = answer.offer((BigInteger) e.getMessage());
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assert offered;
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}
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});
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}
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}
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@Override
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public void exceptionCaught(
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ChannelHandlerContext ctx, ExceptionEvent e) {
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logger.log(
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Level.WARNING,
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"Unexpected exception from downstream.",
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e.getCause());
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e.getChannel().close();
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}
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private void sendNumbers(ChannelStateEvent e) {
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Channel channel = e.getChannel();
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while (channel.isWritable()) {
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if (i <= count) {
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channel.write(Integer.valueOf(i));
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i ++;
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} else {
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break;
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}
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}
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}
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}
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