~vcs-imports/xena/trunk

/*

 * 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.

 */

package org.apache.xerces.jaxp.validation;

import java.lang.ref.WeakReference;

import org.apache.xerces.xni.grammars.XMLGrammarPool;

/**

 * <p>An implementation of Schema for W3C XML Schemas

 * that keeps a weak reference to its grammar pool. If

 * no validators currently have a reference to the

 * grammar pool, the garbage collector is free to reclaim

 * its memory.</p>

 * 

 * @author Michael Glavassevich, IBM

 * @version $Id: WeakReferenceXMLSchema.java,v 1.2 2009/12/10 03:18:25 matthewoliver Exp $

 */

final class WeakReferenceXMLSchema extends AbstractXMLSchema {

    /** Weak reference to grammar pool. */

    private WeakReference fGrammarPool = new WeakReference(null);

    public WeakReferenceXMLSchema() {}

    /*

     * XSGrammarPoolContainer methods

     */

    public synchronized XMLGrammarPool getGrammarPool() {

        XMLGrammarPool grammarPool = (XMLGrammarPool) fGrammarPool.get();

        // If there's no grammar pool then either we haven't created one

        // yet or the garbage collector has already cleaned out the previous one. 

        if (grammarPool == null) {

            grammarPool = new SoftReferenceGrammarPool();

            fGrammarPool = new WeakReference(grammarPool);

        }

        return grammarPool;

    }

    public boolean isFullyComposed() {

        return false;

    }

} // WeakReferenceXMLSchema