/*
 * 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: xamjadmin@users.sourceforge.net
 */
package org.cobra_grendel.js;

import java.io.Serializable;
import java.lang.ref.WeakReference;
import java.util.Map;
import java.util.WeakHashMap;

public class JavaClassWrapperFactory implements Serializable
{
    /**
	 * 
	 */
    private static final long serialVersionUID = 1L;
    private static JavaClassWrapperFactory instance;

    public static JavaClassWrapperFactory getInstance()
    {
        if (instance == null)
        {
            synchronized (JavaClassWrapperFactory.class)
            {
                if (instance == null)
                {
                    instance = new JavaClassWrapperFactory();
                }
            }
        }
        return instance;
    }

    private final Map classWrappers = new WeakHashMap();

    private JavaClassWrapperFactory()
    {
    }

    public JavaClassWrapper getClassWrapper(final 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) classWrappers.get(clazz);
            JavaClassWrapper jcw = null;
            if (jcwr != null)
            {
                jcw = (JavaClassWrapper) jcwr.get();
            }
            if (jcw == null)
            {
                jcw = new JavaClassWrapper(clazz);
                classWrappers.put(clazz, new WeakReference(jcw));
            }
            return jcw;
        }
    }
}