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Common code used with both ARC and WARC archives. Also include some useful utilities to use when working with ARC/WARC/GZip files.

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/**
 * Java Web Archive Toolkit - Software to read and validate ARC, WARC
 * and GZip files. (http://jwat.org/)
 * Copyright 2011-2012 Netarkivet.dk (http://netarkivet.dk/)
 *
 * 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.jwat.archive;

import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.Semaphore;

public class ManagedPayloadManager {

    public static final int DEFAULT_COPY_BUFFER_SIZE = 8192;

    public static final int DEFAULT_IN_MEMORY_BUFFER_SIZE = 10*1024*1024;

    public static ManagedPayloadManager getInstance() {
        return getInstance(DEFAULT_COPY_BUFFER_SIZE, DEFAULT_IN_MEMORY_BUFFER_SIZE);
    }

    public static ManagedPayloadManager getInstance(int copyBufferSize, int inMemorybufferSize) {
        ManagedPayloadManager mpm = new ManagedPayloadManager();
        mpm.copyBufferSize = copyBufferSize;
        mpm.inMemorybufferSize = inMemorybufferSize;
        return mpm;
    }

    protected Semaphore queueLock = new Semaphore(1);

    protected ConcurrentLinkedQueue managedPayloadQueue = new ConcurrentLinkedQueue();

    protected int copyBufferSize;

    protected int inMemorybufferSize;

    public ManagedPayload checkout() {
        ManagedPayload managedPayload = null;
        queueLock.acquireUninterruptibly();
        managedPayload = managedPayloadQueue.poll();
        if (managedPayload == null) {
            managedPayload = new ManagedPayload(copyBufferSize, inMemorybufferSize);
        }
        if (!managedPayload.lock.tryAcquire()) {
            throw new IllegalStateException();
        }
        queueLock.release();
        return managedPayload;
    }

    public void checkin(ManagedPayload managedPayload) {
        queueLock.acquireUninterruptibly();
        managedPayload.lock.release();
        managedPayloadQueue.add(managedPayload);
        queueLock.release();
    }

}