1/*-
2 * See the file LICENSE for redistribution information.
3 *
4 * Copyright (c) 2002,2008 Oracle.  All rights reserved.
5 *
6 * $Id: PrimaryKeyValueAdapter.java,v 1.1 2008/02/07 17:12:26 mark Exp $
7 */
8
9package com.sleepycat.persist;
10
11import com.sleepycat.bind.EntryBinding;
12import com.sleepycat.db.DatabaseEntry;
13
14/**
15 * A ValueAdapter where the "value" is the primary key.
16 *
17 * @author Mark Hayes
18 */
19class PrimaryKeyValueAdapter<V> implements ValueAdapter<V> {
20
21    private EntryBinding keyBinding;
22
23    PrimaryKeyValueAdapter(Class<V> keyClass, EntryBinding keyBinding) {
24        this.keyBinding = keyBinding;
25    }
26
27    public DatabaseEntry initKey() {
28        return new DatabaseEntry();
29    }
30
31    public DatabaseEntry initPKey() {
32        return new DatabaseEntry();
33    }
34
35    public DatabaseEntry initData() {
36        return BasicIndex.NO_RETURN_ENTRY;
37    }
38
39    public void clearEntries(DatabaseEntry key,
40                             DatabaseEntry pkey,
41                             DatabaseEntry data) {
42        key.setData(null);
43        pkey.setData(null);
44    }
45
46    public V entryToValue(DatabaseEntry key,
47                          DatabaseEntry pkey,
48                          DatabaseEntry data) {
49        return (V) keyBinding.entryToObject(pkey);
50    }
51
52    public void valueToData(V value, DatabaseEntry data) {
53        throw new UnsupportedOperationException
54            ("Cannot change the data in a key-only index");
55    }
56}
57