content: /*
   * 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 mf.org.apache.xerces.jaxp.validation;
  
  import java.lang.ref.WeakReference;
  
  import mf.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 447235 2006-09-18 05:01:44Z mrglavas $
   */
  final class WeakReferenceXMLSchema extends AbstractXMLSchema {
  
      /**
       * Weak reference to grammar pool.
       */
      private WeakReference fGrammarPool = new WeakReference(null);
  
      public WeakReferenceXMLSchema() {
      }
      
      /*
       * XSGrammarPoolContainer methods
       */
  
      @Override
      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;
      }
  
      @Override
      public boolean isFullyComposed() {
          return false;
      }
  
  } // WeakReferenceXMLSchema
  