KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > sleepycat > persist > DataValueAdapter


1 /*-
2  * See the file LICENSE for redistribution information.
3  *
4  * Copyright (c) 2002,2006 Oracle. All rights reserved.
5  *
6  * $Id: DataValueAdapter.java,v 1.6 2006/10/30 21:14:30 bostic Exp $
7  */
8
9 package com.sleepycat.persist;
10
11 import com.sleepycat.bind.EntryBinding;
12 import com.sleepycat.je.DatabaseEntry;
13
14 /**
15  * A ValueAdapter where the "value" is the data, although the data in this case
16  * is the primary key in a KeysIndex.
17  *
18  * @author Mark Hayes
19  */
20 class DataValueAdapter<V> implements ValueAdapter<V> {
21
22     private EntryBinding dataBinding;
23
24     DataValueAdapter(Class JavaDoc<V> keyClass, EntryBinding dataBinding) {
25         this.dataBinding = dataBinding;
26     }
27
28     public DatabaseEntry initKey() {
29         return new DatabaseEntry();
30     }
31
32     public DatabaseEntry initPKey() {
33         return null;
34     }
35
36     public DatabaseEntry initData() {
37         return new DatabaseEntry();
38     }
39     
40     public void clearEntries(DatabaseEntry key,
41                              DatabaseEntry pkey,
42                              DatabaseEntry data) {
43         key.setData(null);
44         data.setData(null);
45     }
46
47     public V entryToValue(DatabaseEntry key,
48                           DatabaseEntry pkey,
49                           DatabaseEntry data) {
50         return (V) dataBinding.entryToObject(data);
51     }
52
53     public void valueToData(V value, DatabaseEntry data) {
54         throw new UnsupportedOperationException JavaDoc
55             ("Cannot change the data in a key-only index");
56     }
57 }
58
Popular Tags