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Java > Open Source Codes > com > sleepycat > bind > serial > TupleSerialBinding


1 /*-
2  * See the file LICENSE for redistribution information.
3  *
4  * Copyright (c) 2000,2006 Oracle. All rights reserved.
5  *
6  * $Id: TupleSerialBinding.java,v 1.24 2006/10/30 21:14:07 bostic Exp $
7  */
8
9 package com.sleepycat.bind.serial;
10
11 import com.sleepycat.bind.EntityBinding;
12 import com.sleepycat.bind.tuple.TupleBase;
13 import com.sleepycat.bind.tuple.TupleInput;
14 import com.sleepycat.bind.tuple.TupleOutput;
15 import com.sleepycat.je.DatabaseEntry;
16
17 /**
18  * An abstract <code>EntityBinding</code> that treats an entity's key entry as
19  * a tuple and its data entry as a serialized object.
20  *
21  * <p>This class takes care of serializing and deserializing the data entry,
22  * and converting the key entry to/from {@link TupleInput} and {@link
23  * TupleOutput} objects. Its three abstract methods must be implemented by a
24  * concrete subclass to convert these objects to/from an entity object.</p>
25  * <ul>
26  * <li> {@link #entryToObject(TupleInput,Object)} </li>
27  * <li> {@link #objectToKey(Object,TupleOutput)} </li>
28  * <li> {@link #objectToData(Object)} </li>
29  * </ul>
30  *
31  * @author Mark Hayes
32  */
33 public abstract class TupleSerialBinding extends TupleBase
34     implements EntityBinding {
35
36     protected SerialBinding dataBinding;
37
38     /**
39      * Creates a tuple-serial entity binding.
40      *
41      * @param classCatalog is the catalog to hold shared class information and
42      * for a database should be a {@link StoredClassCatalog}.
43      *
44      * @param baseClass is the base class.
45      */
46     public TupleSerialBinding(ClassCatalog classCatalog,
47                               Class JavaDoc baseClass) {
48
49         this(new SerialBinding(classCatalog, baseClass));
50     }
51
52     /**
53      * Creates a tuple-serial entity binding.
54      *
55      * @param dataBinding is the data binding.
56      */
57     public TupleSerialBinding(SerialBinding dataBinding) {
58
59         this.dataBinding = dataBinding;
60     }
61
62     // javadoc is inherited
63 public Object JavaDoc entryToObject(DatabaseEntry key, DatabaseEntry data) {
64
65         return entryToObject(entryToInput(key),
66                              dataBinding.entryToObject(data));
67     }
68
69     // javadoc is inherited
70 public void objectToKey(Object JavaDoc object, DatabaseEntry key) {
71
72         TupleOutput output = getTupleOutput(object);
73         objectToKey(object, output);
74         outputToEntry(output, key);
75     }
76
77     // javadoc is inherited
78 public void objectToData(Object JavaDoc object, DatabaseEntry data) {
79
80         object = objectToData(object);
81         dataBinding.objectToEntry(object, data);
82     }
83
84     /**
85      * Constructs an entity object from {@link TupleInput} key entry and
86      * deserialized data entry objects.
87      *
88      * @param keyInput is the {@link TupleInput} key entry object.
89      *
90      * @param dataInput is the deserialized data entry object.
91      *
92      * @return the entity object constructed from the key and data.
93      */
94     public abstract Object JavaDoc entryToObject(TupleInput keyInput,
95                                          Object JavaDoc dataInput);
96
97     /**
98      * Extracts a key tuple from an entity object.
99      *
100      * @param object is the entity object.
101      *
102      * @param keyOutput is the {@link TupleOutput} to which the key should be
103      * written.
104      */
105     public abstract void objectToKey(Object JavaDoc object, TupleOutput keyOutput);
106
107     /**
108      * Extracts a data object from an entity object.
109      *
110      * @param object is the entity object.
111      *
112      * @return the deserialized data object.
113      */
114     public abstract Object JavaDoc objectToData(Object JavaDoc object);
115 }
116
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