org.rzo.netty.ahessian.io.PushInputStreamConsumer.java Source code

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Here is the source code for org.rzo.netty.ahessian.io.PushInputStreamConsumer.java

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/*******************************************************************************
 * Copyright  2015 rzorzorzo@users.sf.net
 *
 * Licensed 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.rzo.netty.ahessian.io;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

import java.io.InputStream;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.Lock;

import org.rzo.netty.ahessian.Constants;
import org.rzo.netty.ahessian.utils.MyReentrantLock;

public class PushInputStreamConsumer extends ChannelInboundHandlerAdapter {

    volatile Lock _lock = new MyReentrantLock();
    AtomicInteger _consumerThreadsCount = new AtomicInteger(0);

    volatile InputStreamConsumer _consumer;
    volatile Executor _executor;

    public PushInputStreamConsumer(InputStreamConsumer consumer, Executor executor) {
        _consumer = consumer;
        _executor = executor;
    }

    @Override
    public void channelRead(final ChannelHandlerContext ctx, final Object msg) throws Exception {
        // input stream is consumed within a separate thread
        // we return the current worker thread to netty, so that it may continue
        // feeding the input stream
        _executor.execute(new Runnable() {
            public void run() {
                String tName = Thread.currentThread().getName();
                try {
                    PushInputStreamConsumer.this.run(ctx, msg);
                } finally {
                    Thread.currentThread().setName(tName);
                    _consumerThreadsCount.decrementAndGet();
                }
            }
        });

    }

    private void run(ChannelHandlerContext ctx, Object evt) {
        if (_consumer.isBufferEmpty()) {
            // we have nothing to consume
            return;
        }

        if (_consumerThreadsCount.incrementAndGet() > 2) {
            // there is already a thread consuming and another at the gate to
            // consume the last chunk
            _consumerThreadsCount.decrementAndGet();
            return;
        }

        Thread.currentThread().setName("ahessian-PushInputStreamConsumer-#" + _consumerThreadsCount.get());

        // consume only with one thread at a time
        _lock.lock();
        try {
            _consumer.consume(ctx, (InputStream) evt);
        } catch (Exception ex) {
            Constants.ahessianLogger.warn("", ex);
        } finally {
            _consumerThreadsCount.decrementAndGet();
            _lock.unlock();
        }

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        _lock.lock();
        try {
            _consumer.setContext(ctx);
        } finally {
            _lock.unlock();
        }
        ctx.fireChannelActive();
    }

}