subprojects/s4-comm/src/main/java/org/apache/s4/comm/QueueingListener.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.apache.s4.comm;

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

import org.apache.s4.base.Listener;

import com.google.inject.Inject;
import com.google.inject.name.Named;

public class QueueingListener implements Listener, Runnable {
    private Listener listener;
    private BlockingQueue<byte[]> queue;
    private long dropCount = 0;
    private volatile Thread thread;

    @Inject
    public QueueingListener(@Named("ll") Listener listener, @Named("comm.queue_listener_size") int queueSize) {
        this.listener = listener;
        queue = new LinkedBlockingQueue<byte[]>(queueSize);
    }

    public long getDropCount() {
        return dropCount;
    }

    public void start() {
        if (thread != null) {
            throw new IllegalStateException("QueueingListener is already started");
        }
        thread = new Thread(this, "QueueingListener");
        thread.start();
    }

    public void stop() {
        if (thread == null) {
            throw new IllegalStateException("QueueingListener is already stopped");
        }
        thread.interrupt();
        thread = null;
    }

    @Override
    public byte[] recv() {
        try {
            // System.out.println("QueueingListener: About to take message from queue");
            return queue.take();
        } catch (InterruptedException ie) {
            Thread.currentThread().interrupt();
            return null;
        }
    }

    public int getPartitionId() {
        return listener.getPartitionId();
    }

    public void run() {
        while (!Thread.interrupted()) {
            byte[] message = listener.recv();
            if (!queue.offer(message)) {
                dropCount++;
            } else {
                // System.out.println("QueueingListener: Adding message of size "
                // + message.length + " to queue");
            }
        }
    }

    @Override
    public void close() {
        // TODO Auto-generated method stub

    }
}