DeletedBtreeExtent


1   /*
2    * The contents of this file are subject to the terms of the Common Development
3    * and Distribution License (the License). You may not use this file except in
4    * compliance with the License.
5    *
6    * You can obtain a copy of the License at http://www.netbeans.org/cddl.html
7    * or http://www.netbeans.org/cddl.txt.
8    *
9    * When distributing Covered Code, include this CDDL Header Notice in each file
10   * and include the License file at http://www.netbeans.org/cddl.txt.
11   * If applicable, add the following below the CDDL Header, with the fields
12   * enclosed by brackets [] replaced by your own identifying information:
13   * "Portions Copyrighted [year] [name of copyright owner]"
14   *
15   * The Original Software is NetBeans. The Initial Developer of the Original
16   * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
17   * Microsystems, Inc. All Rights Reserved.
18   */
19  package org.netbeans.mdr.persistence.btreeimpl.btreestorage;
20  
21  import java.io.*;
22  import java.util.*;
23  
24  /** This is an extent which is part of a record which has been deleted,
25  * and is available for reuse
26  */
27  class DeletedBtreeExtent extends BtreeExtent {
28  
29      /** Create a new DeletedBtreeExtent
30      * @param file the BtreeDataFile this extent will belong to
31      * @param chunkNum where this extent begins
32      * @param numChunks the size of the extent
33      */
34      DeletedBtreeExtent(BtreeDataFile file, int chunkNum, short numChunks) {
35          super(file, chunkNum, numChunks);
36      }
37  
38      /** Convert an active extent to a deleted one when a record is
39      * deleted
40      * @param extent the extent being deleted
41      */
42      DeletedBtreeExtent(ActiveBtreeExtent extent) {
43          super(extent);
44          headerIsDirty = true;
45          owner.deleteExtent(this);
46      }
47          
48      /** read type-specific header data.  A no-op, since DeletedBtreeExtents
49      * have none.
50      * @param buffer the buffer to read from
51      * @param offset the offset to being reading at
52      */
53      void readHeaderFromPage(byte buffer[], IntHolder offset) {
54          // we have no type-specific data
55      }
56  
57      /** Get the magic number for this type of extent
58      * @return the magic number
59      */
60      short getMagic() {
61          return DELETED_MAGIC;
62      }
63  
64      /** write the type-specific part of the header.  A no-op, since 
65      * DeletedBtreeExtents have none.
66      * @param page the page to write to
67      * @param offset the offset to begin an
68      */
69      protected void writeHeaderToPage(CachedPage page, int offset) {
70          // we have no type-specific data
71      }
72  
73      /** return type of extent
74      * @return IS_DELETED
75      */
76      byte getType() {
77          return IS_DELETED;
78      }
79  
80      /** return name of type of extent
81      * @return DELETED_NAME
82      */
83      String   getTypeName() {
84          return DELETED_NAME;
85      }
86  }
87
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags