View Javadoc

1   /*
2    * Copyright 2004 Charles Blaxland
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  package mnemosyne.archiver;
17  
18  import mnemosyne.core.Persistable;
19  
20  import java.io.ObjectOutputStream;
21  import java.io.OutputStream;
22  import java.io.IOException;
23  
24  import org.apache.commons.logging.LogFactory;
25  import org.apache.commons.logging.Log;
26  
27  /***
28   * @version $Id: ArchiveOutputStream.java,v 1.1.1.1 2004/08/07 06:40:50 charlesblaxland Exp $
29   */
30  public class ArchiveOutputStream extends ObjectOutputStream
31  {
32      private static final Log log = LogFactory.getLog(ArchiveOutputStream.class);
33  
34      public ArchiveOutputStream(OutputStream out)
35              throws IOException
36      {
37          super(out);
38          enableReplaceObject(true);
39      }
40  
41      protected Object replaceObject(Object obj) throws IOException
42      {
43          if (obj instanceof Persistable)
44          {
45              Persistable persistable = (Persistable) obj;
46              if (!persistable.isArchiveVersion())
47              {
48                  obj = persistable.getPersistentObject();
49                  if (log.isTraceEnabled())
50                  {
51                      log.trace("Replaced object of type " + persistable.getClass().getName() + " with persistent object " + obj);
52                  }
53              }
54          }
55  
56          return obj;
57      }
58  }