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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * 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.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

import java.math.BigInteger;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

/**
 * 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 SimpleChannelInboundHandler {

    private ChannelHandlerContext ctx;
    private int receivedMessages;
    private int next = 1;
    final BlockingQueue answer = new LinkedBlockingQueue();

    public BigInteger getFactorial() {
        boolean interrupted = false;
        try {
            for (;;) {
                try {
                    return answer.take();
                } catch (InterruptedException ignore) {
                    interrupted = true;
                }
            }
        } finally {
            if (interrupted) {
                Thread.currentThread().interrupt();
            }
        }
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        this.ctx = ctx;
        sendNumbers();
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, final BigInteger msg) {
        receivedMessages ++;
        if (receivedMessages == FactorialClient.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) {
        cause.printStackTrace();
        ctx.close();
    }

    private void sendNumbers() {
        // Do not send more than 4096 numbers.
        ChannelFuture future = null;
        for (int i = 0; i < 4096 && next <= FactorialClient.COUNT; i++) {
            future = ctx.write(Integer.valueOf(next));
            next++;
        }
        if (next <= FactorialClient.COUNT) {
            assert future != null;
            future.addListener(numberSender);
        }
        ctx.flush();
    }

    private final ChannelFutureListener numberSender = new ChannelFutureListener() {
        @Override
        public void operationComplete(ChannelFuture future) throws Exception {
            if (future.isSuccess()) {
                sendNumbers();
            } else {
                future.cause().printStackTrace();
                future.channel().close();
            }
        }
    };
}