105 lines
3.4 KiB
Java
105 lines
3.4 KiB
Java
/*
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* Copyright 2012 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 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.SimpleChannelInboundHandler;
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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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/**
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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 SimpleChannelInboundHandler<BigInteger> {
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private ChannelHandlerContext ctx;
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private int receivedMessages;
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private int next = 1;
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final BlockingQueue<BigInteger> answer = new LinkedBlockingQueue<>();
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public BigInteger getFactorial() {
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boolean interrupted = false;
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try {
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for (;;) {
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try {
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return answer.take();
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} catch (InterruptedException ignore) {
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interrupted = true;
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}
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}
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} finally {
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if (interrupted) {
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Thread.currentThread().interrupt();
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}
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}
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}
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@Override
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public void channelActive(ChannelHandlerContext ctx) {
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this.ctx = ctx;
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sendNumbers();
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}
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@Override
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public void messageReceived(ChannelHandlerContext ctx, final BigInteger msg) {
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receivedMessages ++;
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if (receivedMessages == FactorialClient.COUNT) {
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// Offer the answer after closing the connection.
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ctx.channel().close().addListener((ChannelFutureListener) future -> {
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boolean offered = answer.offer(msg);
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assert offered;
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});
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}
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}
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@Override
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public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
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cause.printStackTrace();
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ctx.close();
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}
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private void sendNumbers() {
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// Do not send more than 4096 numbers.
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ChannelFuture future = null;
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for (int i = 0; i < 4096 && next <= FactorialClient.COUNT; i++) {
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future = ctx.write(Integer.valueOf(next));
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next++;
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}
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if (next <= FactorialClient.COUNT) {
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assert future != null;
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future.addListener(numberSender);
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}
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ctx.flush();
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}
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private final ChannelFutureListener numberSender = future -> {
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if (future.isSuccess()) {
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sendNumbers();
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} else {
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future.cause().printStackTrace();
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future.channel().close();
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}
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};
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}
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