/*
    GNU LESSER GENERAL PUBLIC LICENSE
    Copyright (C) 2006 The Lobo Project

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Contact info: lobochief@users.sourceforge.net
*/
package org.lobobrowser.js;

import java.util.*;
import java.lang.ref.*;

public class JavaClassWrapperFactory {
	private static JavaClassWrapperFactory instance;
	private final Map classWrappers = new WeakHashMap();
	
	private JavaClassWrapperFactory() { }
	
	public static JavaClassWrapperFactory getInstance() {
		if(instance == null) {
			synchronized(JavaClassWrapperFactory.class) {
				if(instance == null) {
					instance = new JavaClassWrapperFactory();
				}
			}
		}
		return instance;
	}
	
	public JavaClassWrapper getClassWrapper(Class clazz) {
		synchronized(this) {
			//WeakHashMaps where the value refers to
			//the key will retain keys. Must make it
			//refer to the value weakly too.
			WeakReference jcwr = (WeakReference) this.classWrappers.get(clazz);
			JavaClassWrapper jcw = null;
			if(jcwr != null) {
				jcw = (JavaClassWrapper) jcwr.get();
			}
			if(jcw == null) {
				jcw = new JavaClassWrapper(clazz);
				this.classWrappers.put(clazz, new WeakReference(jcw));
			}
			return jcw;
		}
	}
}