/*
* 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 io.netty.example.factorial;
import io.netty.buffer.MessageBuf;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundMessageHandlerAdapter;
import java.math.BigInteger;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Handler for a client-side channel. This handler maintains stateful
* information which is specific to a certain channel using member variables.
* Therefore, an instance of this handler can cover only one channel. You have
* to create a new handler instance whenever you create a new channel and insert
* this handler to avoid a race condition.
*/
public class FactorialClientHandler extends ChannelInboundMessageHandlerAdapter<BigInteger> {
private static final Logger logger = Logger.getLogger(
FactorialClientHandler.class.getName());
private ChannelHandlerContext ctx;
private int i = 1;
private int receivedMessages;
private final int count;
final BlockingQueue<BigInteger> answer = new LinkedBlockingQueue<BigInteger>();
public FactorialClientHandler(int count) {
this.count = count;
}
public BigInteger getFactorial() {
boolean interrupted = false;
for (;;) {
try {
BigInteger factorial = answer.take();
if (interrupted) {
Thread.currentThread().interrupt();
}
return factorial;
} catch (InterruptedException e) {
interrupted = true;
}
}
}
@Override
public void channelActive(ChannelHandlerContext ctx) {
this.ctx = ctx;
sendNumbers();
}
@Override
public void messageReceived(
ChannelHandlerContext ctx, final BigInteger msg) {
receivedMessages ++;
if (receivedMessages == count) {
// Offer the answer after closing the connection.
ctx.channel().close().addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
boolean offered = answer.offer(msg);
assert offered;
}
});
}
}
@Override
public void exceptionCaught(
ChannelHandlerContext ctx, Throwable cause) throws Exception {
logger.log(
Level.WARNING,
"Unexpected exception from downstream.", cause);
ctx.close();
}
private void sendNumbers() {
// Do not send more than 4096 numbers.
boolean finished = false;
MessageBuf<Object> out = ctx.nextOutboundMessageBuffer();
while (out.size() < 4096) {
if (i <= count) {
out.add(Integer.valueOf(i));
i ++;
} else {
finished = true;
break;
}
}
ChannelFuture f = ctx.flush();
if (!finished) {
f.addListener(numberSender);
}
}
private final ChannelFutureListener numberSender = new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (future.isSuccess()) {
sendNumbers();
}
}
};
}