/*
* Copyright 2009 Red Hat, Inc.
*
* Red Hat 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 org.jboss.netty.example.factorial;
import java.math.BigInteger;
import java.util.Formatter;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jboss.netty.channel.ChannelEvent;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
/**
* Handler for a server-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.
*
* @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
* @author <a href="http://gleamynode.net/">Trustin Lee</a>
*
* @version $Rev: 2121 $, $Date: 2010-02-02 09:38:07 +0900 (Tue, 02 Feb 2010) $
*/
public class FactorialServerHandler extends SimpleChannelUpstreamHandler {
private static final Logger logger = Logger.getLogger(
FactorialServerHandler.class.getName());
// Stateful properties.
private int lastMultiplier = 1;
private BigInteger factorial = new BigInteger(new byte[] { 1 });
@Override
public void handleUpstream(
ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
if (e instanceof ChannelStateEvent) {
logger.info(e.toString());
}
super.handleUpstream(ctx, e);
}
@Override
public void messageReceived(
ChannelHandlerContext ctx, MessageEvent e) {
// Calculate the cumulative factorial and send it to the client.
BigInteger number;
if (e.getMessage() instanceof BigInteger) {
number = (BigInteger) e.getMessage();
} else {
number = new BigInteger(e.getMessage().toString());
}
lastMultiplier = number.intValue();
factorial = factorial.multiply(number);
e.getChannel().write(factorial);
}
@Override
public void channelDisconnected(ChannelHandlerContext ctx,
ChannelStateEvent e) throws Exception {
logger.info(new Formatter().format(
"Factorial of %,d is: %,d", lastMultiplier, factorial).toString());
}
@Override
public void exceptionCaught(
ChannelHandlerContext ctx, ExceptionEvent e) {
logger.log(
Level.WARNING,
"Unexpected exception from downstream.",
e.getCause());
e.getChannel().close();
}
}