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


1 /*-
2  * See the file LICENSE for redistribution information.
3  *
4  * Copyright (c) 2000,2006 Oracle. All rights reserved.
5  *
6  * $Id: TupleTupleBinding.java,v 1.24 2006/10/30 21:14:08 bostic Exp $
7  */
8
9 package com.sleepycat.bind.tuple;
10
11 import com.sleepycat.bind.EntityBinding;
12 import com.sleepycat.je.DatabaseEntry;
13
14 /**
15  * An abstract <code>EntityBinding</code> that treats an entity's key entry and
16  * data entry as tuples.
17  *
18  * <p>This class takes care of converting the entries to/from {@link
19  * TupleInput} and {@link TupleOutput} objects. Its three abstract methods
20  * must be implemented by a concrete subclass to convert between tuples and
21  * entity objects.</p>
22  * <ul>
23  * <li> {@link #entryToObject(TupleInput,TupleInput)} </li>
24  * <li> {@link #objectToKey(Object,TupleOutput)} </li>
25  * <li> {@link #objectToData(Object,TupleOutput)} </li>
26  * </ul>
27  *
28  * @author Mark Hayes
29  */
30 public abstract class TupleTupleBinding extends TupleBase
31     implements EntityBinding {
32
33     /**
34      * Creates a tuple-tuple entity binding.
35      */
36     public TupleTupleBinding() {
37     }
38
39     // javadoc is inherited
40 public Object JavaDoc entryToObject(DatabaseEntry key, DatabaseEntry data) {
41
42         return entryToObject(TupleBinding.entryToInput(key),
43                              TupleBinding.entryToInput(data));
44     }
45
46     // javadoc is inherited
47 public void objectToKey(Object JavaDoc object, DatabaseEntry key) {
48
49         TupleOutput output = getTupleOutput(object);
50         objectToKey(object, output);
51         outputToEntry(output, key);
52     }
53
54     // javadoc is inherited
55 public void objectToData(Object JavaDoc object, DatabaseEntry data) {
56
57         TupleOutput output = getTupleOutput(object);
58         objectToData(object, output);
59         outputToEntry(output, data);
60     }
61
62     // abstract methods
63
64     /**
65      * Constructs an entity object from {@link TupleInput} key and data
66      * entries.
67      *
68      * @param keyInput is the {@link TupleInput} key entry object.
69      *
70      * @param dataInput is the {@link TupleInput} data entry object.
71      *
72      * @return the entity object constructed from the key and data.
73      */
74     public abstract Object JavaDoc entryToObject(TupleInput keyInput,
75                                          TupleInput dataInput);
76
77     /**
78      * Extracts a key tuple from an entity object.
79      *
80      * @param object is the entity object.
81      *
82      * @param output is the {@link TupleOutput} to which the key should be
83      * written.
84      */
85     public abstract void objectToKey(Object JavaDoc object, TupleOutput output);
86
87     /**
88      * Extracts a key tuple from an entity object.
89      *
90      * @param object is the entity object.
91      *
92      * @param output is the {@link TupleOutput} to which the data should be
93      * written.
94      */
95     public abstract void objectToData(Object JavaDoc object, TupleOutput output);
96 }
97
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