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1   package org.apache.ojb.broker.cache;
2   
3   /* Copyright 2002-2005 The Apache Software Foundation
4    *
5    * Licensed under the Apache License, Version 2.0 (the "License");
6    * you may not use this file except in compliance with the License.
7    * You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  import org.apache.ojb.broker.PersistenceBroker;
19  import org.apache.ojb.broker.util.logging.Logger;
20  import org.apache.ojb.broker.util.logging.LoggerFactory;
21  
22  /**
23   * Factory for {@link ObjectCache} implementation classes.
24   * Each given {@link org.apache.ojb.broker.PersistenceBroker}
25   * was associated with its own <code>ObjectCache</code> instance
26   * and vice versa.
27   *
28   * @author <a href="mailto:thma@apache.org">Thomas Mahler<a>
29   * @version $Id: ObjectCacheFactory.java,v 1.1 2007-08-24 22:17:29 ewestfal Exp $
30   */
31  
32  public class ObjectCacheFactory
33  {
34      private Logger log = LoggerFactory.getLogger(ObjectCacheFactory.class);
35  
36      private static ObjectCacheFactory singleton = new ObjectCacheFactory();
37  
38      /**
39       * Get the ObjectCacheFactory instance.
40       */
41      public static ObjectCacheFactory getInstance()
42      {
43          return singleton;
44      }
45  
46      private ObjectCacheFactory()
47      {
48      }
49  
50      /**
51       * Creates a new {@link ObjectCacheInternal} instance. Each <tt>ObjectCache</tt>
52       * implementation was wrapped by a {@link CacheDistributor} and the distributor
53       * was wrapped by {@link MaterializationCache}.
54       *
55       * @param broker The PB instance to associate with the cache instance
56       */
57      public MaterializationCache createObjectCache(PersistenceBroker broker)
58      {
59          CacheDistributor cache = null;
60          try
61          {
62              log.info("Start creating new ObjectCache instance");
63              /*
64              1.
65              if default cache was not found,
66              create an new instance of the default cache specified in the
67              configuration.
68              2.
69              Then instantiate AllocatorObjectCache to handle
70              per connection/ per class caching instances.
71              3.
72              To support intern operations we wrap ObjectCache with an
73              InternalObjectCache implementation
74              */
75              cache = new CacheDistributor(broker);
76              log.info("Instantiate new " + cache.getClass().getName() + " for PB instance " + broker);
77          }
78          catch(Exception e)
79          {
80              log.error("Error while initiation, please check your configuration" +
81                      " files and the used implementation class", e);
82          }
83          log.info("New ObjectCache instance was created");
84          return new MaterializationCache(cache);
85      }
86  }