oz.hadoop.yarn.api.net.ByteBufferPool.java Source code

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Here is the source code for oz.hadoop.yarn.api.net.ByteBufferPool.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 oz.hadoop.yarn.api.net;

import java.nio.ByteBuffer;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Internal utility class used by Socket handlers ({@link ApplicationContainerServer} & {@link ApplicationContainerClient}) 
 * in this package to manage pools of {@link ByteBuffer} essentially allowing used {@link ByteBuffer}s to be reused 
 * instead of reallocating memory.
 * 
 * @author Oleg Zhurakousky
 *
 */
class ByteBufferPool {

    private final Log logger = LogFactory.getLog(ByteBufferPool.class);

    private static final int DEF_SIZE = 1048576; // 1MB

    private static final int BUFFER_COUNT = 10;

    private final BlockingQueue<ByteBuffer> bufferQueue;

    private final int initialBufferSize;

    /**
     * 
     */
    public ByteBufferPool() {
        this(DEF_SIZE, BUFFER_COUNT);
    }

    /**
     * 
     * @param initialBufferSize
     * @param bufferCount
     */
    public ByteBufferPool(int initialBufferSize, int bufferCount) {
        this.initialBufferSize = initialBufferSize;
        this.bufferQueue = new ArrayBlockingQueue<>(bufferCount);
    }

    /**
     * Will return the first available {@link ByteBuffer} from the pool
     * or new one
     */
    public ByteBuffer poll() {
        ByteBuffer buffer = this.bufferQueue.poll();
        if (buffer == null) {
            if (logger.isDebugEnabled()) {
                logger.debug("Creating new buffer with capacity: " + this.initialBufferSize);
            }
            buffer = ByteBuffer.allocate(this.initialBufferSize);
        } else {
            logger.trace("Polled buffer");
        }
        buffer.clear();
        return buffer;
    }

    /**
     * Will release buffer to a common pool or discard if queue is full.
     * 
     * @param buffer
     */
    public void release(ByteBuffer buffer) {
        logger.trace("Releasing buffer");
        this.bufferQueue.offer(buffer);
    }
}