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Java > Open Source Codes > com > sleepycat > bind > tuple > TupleTupleMarshalledKeyCreator


1 /*-
2  * See the file LICENSE for redistribution information.
3  *
4  * Copyright (c) 2000,2006 Oracle. All rights reserved.
5  *
6  * $Id: TupleTupleMarshalledKeyCreator.java,v 1.27 2006/10/30 21:14:09 bostic Exp $
7  */
8
9 package com.sleepycat.bind.tuple;
10
11 /**
12  * A concrete key creator that works in conjunction with a {@link
13  * TupleTupleMarshalledBinding}. This key creator works by calling the
14  * methods of the {@link MarshalledTupleKeyEntity} interface to create and
15  * clear the index key.
16  *
17  * <p>Note that a marshalled tuple key creator is somewhat less efficient
18  * than a non-marshalled key tuple creator because more conversions are
19  * needed. A marshalled key creator must convert the entry to an object in
20  * order to create the key, while an unmarshalled key creator does not.</p>
21  *
22  * @author Mark Hayes
23  */
24 public class TupleTupleMarshalledKeyCreator extends TupleTupleKeyCreator {
25
26     private String JavaDoc keyName;
27     private TupleTupleMarshalledBinding binding;
28
29     /**
30      * Creates a tuple-tuple marshalled key creator.
31      *
32      * @param binding is the binding used for the tuple-tuple entity.
33      *
34      * @param keyName is the key name passed to the {@link
35      * MarshalledTupleKeyEntity#marshalSecondaryKey} method to identify the
36      * index key.
37      */
38     public TupleTupleMarshalledKeyCreator(TupleTupleMarshalledBinding binding,
39                                           String JavaDoc keyName) {
40
41         this.binding = binding;
42         this.keyName = keyName;
43     }
44
45     // javadoc is inherited
46 public boolean createSecondaryKey(TupleInput primaryKeyInput,
47                                       TupleInput dataInput,
48                                       TupleOutput indexKeyOutput) {
49
50         /* The primary key is unmarshalled before marshalling the index key, to
51          * account for cases where the index key includes fields taken from the
52          * primary key.
53          */
54         MarshalledTupleKeyEntity entity = (MarshalledTupleKeyEntity)
55             binding.entryToObject(primaryKeyInput, dataInput);
56
57         return entity.marshalSecondaryKey(keyName, indexKeyOutput);
58     }
59
60     // javadoc is inherited
61 public boolean nullifyForeignKey(TupleInput dataInput,
62                                      TupleOutput dataOutput) {
63
64         // XXX null primary key input below may be unexpected by the binding
65 MarshalledTupleKeyEntity entity = (MarshalledTupleKeyEntity)
66             binding.entryToObject(null, dataInput);
67         if (entity.nullifyForeignKey(keyName)) {
68             binding.objectToData(entity, dataOutput);
69             return true;
70         } else {
71             return false;
72         }
73     }
74 }
75
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