KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > sleepycat > persist > impl > PersistKeyBinding


1 /*-
2  * See the file LICENSE for redistribution information.
3  *
4  * Copyright (c) 2002,2006 Oracle. All rights reserved.
5  *
6  * $Id: PersistKeyBinding.java,v 1.17 2006/10/30 21:14:32 bostic Exp $
7  */
8
9 package com.sleepycat.persist.impl;
10
11 import com.sleepycat.bind.EntryBinding;
12 import com.sleepycat.bind.tuple.TupleBase;
13 import com.sleepycat.je.DatabaseEntry;
14
15 /**
16  * A persistence key binding for a given key class.
17  *
18  * @author Mark Hayes
19  */
20 public class PersistKeyBinding implements EntryBinding {
21
22     Catalog catalog;
23     Format keyFormat;
24     boolean rawAccess;
25
26     /**
27      * Creates a key binding for a given key class.
28      */
29     public PersistKeyBinding(Catalog catalog,
30                              String JavaDoc clsName,
31                              boolean rawAccess) {
32         this.catalog = catalog;
33         keyFormat = catalog.getFormat(clsName);
34         if (keyFormat == null) {
35             throw new IllegalArgumentException JavaDoc
36                 ("Class is not persistent: " + clsName);
37         }
38         if (!keyFormat.isSimple() &&
39             (keyFormat.getClassMetadata() == null ||
40              keyFormat.getClassMetadata().getCompositeKeyFields() == null)) {
41             throw new IllegalArgumentException JavaDoc
42                 ("Key class is not a simple type or a composite key class " +
43                  "(composite keys must include @KeyField annotations): " +
44                  clsName);
45         }
46         this.rawAccess = rawAccess;
47     }
48
49     /**
50      * Creates a key binding dynamically for use by PersistComparator. Formats
51      * are created from scratch rather than using a shared catalog.
52      */
53     PersistKeyBinding(Class JavaDoc cls, String JavaDoc[] compositeFieldOrder) {
54         catalog = SimpleCatalog.getInstance();
55         if (compositeFieldOrder != null) {
56             assert !SimpleCatalog.isSimpleType(cls);
57             keyFormat = new CompositeKeyFormat(cls, null, compositeFieldOrder);
58         } else {
59             assert SimpleCatalog.isSimpleType(cls);
60             keyFormat = catalog.getFormat(cls);
61         }
62         keyFormat.initializeIfNeeded(catalog);
63     }
64
65     /**
66      * Binds bytes to an object for use by PersistComparator as well as
67      * entryToObject.
68      */
69     Object JavaDoc bytesToObject(byte[] bytes, int offset, int length) {
70         return readKey(keyFormat, catalog, bytes, offset, length, rawAccess);
71     }
72
73     /**
74      * Binds bytes to an object for use by PersistComparator as well as
75      * entryToObject.
76      */
77     static Object JavaDoc readKey(Format keyFormat,
78                           Catalog catalog,
79                           byte[] bytes,
80                           int offset,
81                           int length,
82                           boolean rawAccess) {
83         EntityInput input = new RecordInput
84             (catalog, rawAccess, null, 0, bytes, offset, length);
85         return input.readKeyObject(keyFormat);
86     }
87
88     public Object JavaDoc entryToObject(DatabaseEntry entry) {
89         return bytesToObject
90             (entry.getData(), entry.getOffset(), entry.getSize());
91     }
92
93     public void objectToEntry(Object JavaDoc object, DatabaseEntry entry) {
94         RecordOutput output = new RecordOutput(catalog, rawAccess);
95         output.writeKeyObject(object, keyFormat);
96         TupleBase.outputToEntry(output, entry);
97     }
98 }
99
Popular Tags