WeakReferenceXMLSchema


1   /*
2    * Copyright 2005 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package com.sun.org.apache.xerces.internal.jaxp.validation;
18  
19  import java.lang.ref.WeakReference  ;
20  
21  import com.sun.org.apache.xerces.internal.xni.grammars.XMLGrammarPool;
22  
23  /**
24   * <p>An implementation of Schema for W3C XML Schemas
25   * that keeps a weak reference to its grammar pool. If
26   * no validators currently have a reference to the
27   * grammar pool, the garbage collector is free to reclaim
28   * its memory.</p>
29   * 
30   * @author Michael Glavassevich, IBM
31   * @version $Id: WeakReferenceXMLSchema.java,v 1.1.4.1 2005/09/05 11:45:49 sunithareddy Exp $
32   */
33  final class WeakReferenceXMLSchema extends AbstractXMLSchema {
34      
35      /** Weak reference to grammar pool. */
36      private WeakReference   fGrammarPool = new WeakReference  (null);
37  
38      public WeakReferenceXMLSchema() {}
39      
40      /*
41       * XSGrammarPoolContainer methods
42       */
43  
44      public synchronized XMLGrammarPool getGrammarPool() {
45          XMLGrammarPool grammarPool = (XMLGrammarPool) fGrammarPool.get();
46          // If there's no grammar pool then either we haven't created one
47          // yet or the garbage collector has already cleaned out the previous one. 
48          if (grammarPool == null) {
49              grammarPool = new SoftReferenceGrammarPool();
50              fGrammarPool = new WeakReference  (grammarPool);
51          }
52          return grammarPool;
53      }
54  
55      public boolean isFullyComposed() {
56          return false;
57      }
58  
59  } // WeakReferenceXMLSchema
60
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