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Java > Open Source Codes > com > caucho > db > store > ReadBlock


1 /*
2  * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3  *
4  * This file is part of Resin(R) Open Source
5  *
6  * Each copy or derived work must preserve the copyright notice and this
7  * notice unmodified.
8  *
9  * Resin Open Source is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Resin Open Source is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17  * of NON-INFRINGEMENT. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with Resin Open Source; if not, write to the
22  *
23  * Free Software Foundation, Inc.
24  * 59 Temple Place, Suite 330
25  * Boston, MA 02111-1307 USA
26  *
27  * @author Scott Ferguson
28  */

29
30 package com.caucho.db.store;
31
32 import com.caucho.log.Log;
33 import com.caucho.util.L10N;
34
35 import java.util.logging.Logger JavaDoc;
36
37 /**
38  * Represents a versioned row
39  */

40 public class ReadBlock extends Block {
41   private static final Logger JavaDoc log = Log.open(ReadBlock.class);
42   private static final L10N L = new L10N(ReadBlock.class);
43
44   private byte []_buffer;
45
46   ReadBlock(Store store, long blockId)
47   {
48     super(store, blockId);
49
50     _buffer = _freeBuffers.allocate();
51     if (_buffer == null)
52       _buffer = new byte[Store.BLOCK_SIZE];
53   }
54
55   /**
56    * Returns the block's buffer.
57    */

58   public byte []getBuffer()
59   {
60     return _buffer;
61   }
62
63   /**
64    * Called when the block is removed from the cache.
65    */

66   protected void freeImpl()
67   {
68     //System.out.println(this + " FREE-IMPL");
69
synchronized (this) {
70       byte []buffer = _buffer;
71       _buffer = null;
72
73       if (buffer != null)
74     _freeBuffers.free(buffer);
75     }
76   }
77
78   public String JavaDoc toString()
79   {
80     return "ReadBlock[" + getStore() + "," + getBlockId() / Store.BLOCK_SIZE + "]";
81   }
82 }
83
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