1/*-
2 * See the file LICENSE for redistribution information.
3 *
4 * Copyright (c) 2000,2008 Oracle.  All rights reserved.
5 *
6 * $Id: TupleTupleMarshalledBinding.java,v 12.8 2008/02/07 17:12:25 mark Exp $
7 */
8
9package com.sleepycat.bind.tuple;
10
11import com.sleepycat.util.RuntimeExceptionWrapper;
12
13/**
14 * A concrete <code>TupleTupleBinding</code> that delegates to the
15 * <code>MarshalledTupleEntry</code> and
16 * <code>MarshalledTupleKeyEntity</code> interfaces of the entity class.
17 *
18 * <p>This class calls the methods of the {@link MarshalledTupleEntry}
19 * interface to convert between the data entry and entity object.  It calls the
20 * methods of the {@link MarshalledTupleKeyEntity} interface to convert between
21 * the key entry and the entity object.  These two interfaces must both be
22 * implemented by the entity class.</p>
23 *
24 * @author Mark Hayes
25 */
26public class TupleTupleMarshalledBinding extends TupleTupleBinding {
27
28    private Class cls;
29
30    /**
31     * Creates a tuple-tuple marshalled binding object.
32     *
33     * <p>The given class is used to instantiate entity objects using
34     * {@link Class#forName}, and therefore must be a public class and have a
35     * public no-arguments constructor.  It must also implement the {@link
36     * MarshalledTupleEntry} and {@link MarshalledTupleKeyEntity}
37     * interfaces.</p>
38     *
39     * @param cls is the class of the entity objects.
40     */
41    public TupleTupleMarshalledBinding(Class cls) {
42
43        this.cls = cls;
44
45        // The entity class will be used to instantiate the entity object.
46        //
47        if (!MarshalledTupleKeyEntity.class.isAssignableFrom(cls)) {
48            throw new IllegalArgumentException(cls.toString() +
49                        " does not implement MarshalledTupleKeyEntity");
50        }
51        if (!MarshalledTupleEntry.class.isAssignableFrom(cls)) {
52            throw new IllegalArgumentException(cls.toString() +
53                        " does not implement MarshalledTupleEntry");
54        }
55    }
56
57    // javadoc is inherited
58    public Object entryToObject(TupleInput keyInput, TupleInput dataInput) {
59
60        // This "tricky" binding returns the stored data as the entity, but
61        // first it sets the transient key fields from the stored key.
62        MarshalledTupleEntry obj;
63        try {
64            obj = (MarshalledTupleEntry) cls.newInstance();
65        } catch (IllegalAccessException e) {
66            throw new RuntimeExceptionWrapper(e);
67        } catch (InstantiationException e) {
68            throw new RuntimeExceptionWrapper(e);
69        }
70        if (dataInput != null) { // may be null if used by key extractor
71            obj.unmarshalEntry(dataInput);
72        }
73        MarshalledTupleKeyEntity entity = (MarshalledTupleKeyEntity) obj;
74        if (keyInput != null) { // may be null if used by key extractor
75            entity.unmarshalPrimaryKey(keyInput);
76        }
77        return entity;
78    }
79
80    // javadoc is inherited
81    public void objectToKey(Object object, TupleOutput output) {
82
83        MarshalledTupleKeyEntity entity = (MarshalledTupleKeyEntity) object;
84        entity.marshalPrimaryKey(output);
85    }
86
87    // javadoc is inherited
88    public void objectToData(Object object, TupleOutput output) {
89
90        MarshalledTupleEntry entity = (MarshalledTupleEntry) object;
91        entity.marshalEntry(output);
92    }
93}
94