SimplePool.java Source code

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Here is the source code for SimplePool.java

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/*
 *  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.
 */

/**
 * Simple object pool. Based on ThreadPool and few other classes
 * 
 * The pool will ignore overflow and return null if empty.
 * 
 * @author Gal Shachor
 * @author Costin Manolache
 */
public final class SimplePool {
    /*
     * Where the threads are held.
     */
    private Object pool[];

    private int max;

    private int last;

    private int current = -1;

    private Object lock;

    public static final int DEFAULT_SIZE = 32;

    static final int debug = 0;

    public SimplePool() {
        this(DEFAULT_SIZE, DEFAULT_SIZE);
    }

    public SimplePool(int size) {
        this(size, size);
    }

    public SimplePool(int size, int max) {
        this.max = max;
        pool = new Object[size];
        this.last = size - 1;
        lock = new Object();
    }

    public void set(Object o) {
        put(o);
    }

    /**
     * Add the object to the pool, silent nothing if the pool is full
     */
    public void put(Object o) {
        synchronized (lock) {
            if (current < last) {
                current++;
                pool[current] = o;
            } else if (current < max) {
                // realocate
                int newSize = pool.length * 2;
                if (newSize > max)
                    newSize = max + 1;
                Object tmp[] = new Object[newSize];
                last = newSize - 1;
                System.arraycopy(pool, 0, tmp, 0, pool.length);
                pool = tmp;
                current++;
                pool[current] = o;
            }
        }
    }

    /**
     * Get an object from the pool, null if the pool is empty.
     */
    public Object get() {
        Object item = null;
        synchronized (lock) {
            if (current >= 0) {
                item = pool[current];
                pool[current] = null;
                current -= 1;
            }
        }
        return item;
    }

    /**
     * Return the size of the pool
     */
    public int getMax() {
        return max;
    }

    /**
     * Number of object in the pool
     */
    public int getCount() {
        return current + 1;
    }

    public void shutdown() {
    }

}