/*
 * $Header: /home/cvs/jakarta-tomcat-jasper/jasper2/src/share/org/apache/jasper/util/SimplePool.java,v 1.2 2002/10/21 20:13:33 luehe Exp $
 * $Revision: 1.2 $
 * $Date: 2002/10/21 20:13:33 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
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 * 5. Products derived from this software may not be called "Apache"
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */

package org.apache.jasper.util;

/**
 * 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
 */
public final class SimplePool  {

    private static final int DEFAULT_SIZE=16;

    /*
     * Where the threads are held.
     */
    private Object pool[];

    private int max;
    private int current=-1;

    private Object lock;
    
    public SimplePool() {
	this.max=DEFAULT_SIZE;
	this.pool=new Object[max];
	this.lock=new Object();
    }
    
    public SimplePool(int max) {
	this.max=max;
	this.pool=new Object[max];
	this.lock=new Object();
    }

    /**
     * Adds the given object to the pool, and does nothing if the pool is full
     */
    public void put(Object o) {
	synchronized( lock ) {
	    if( current < (max-1) ) {
		current += 1;
		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];
		current -= 1;
	    }
	}
	return item;
    }

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