1/*
2 * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25package com.sun.beans.decoder;
26
27/**
28 * This class is intended to handle <null> element.
29 * This element specifies {@code null} value.
30 * It should not contain body or inner elements.
31 * For example:<pre>
32 * &lt;null/&gt;</pre>
33 * is equivalent to {@code null} in Java code.
34 * <p>The following attribute is supported:
35 * <dl>
36 * <dt>id
37 * <dd>the identifier of the variable that is intended to store the result
38 * </dl>
39 *
40 * @since 1.7
41 *
42 * @author Sergey A. Malenkov
43 */
44class NullElementHandler extends ElementHandler implements ValueObject {
45
46    /**
47     * Returns the value of this element.
48     *
49     * @return the value of this element
50     */
51    @Override
52    protected final ValueObject getValueObject() {
53        return this;
54    }
55
56    /**
57     * Returns {@code null}
58     * as a value of &lt;null&gt; element.
59     * This method should be overridden in those handlers
60     * that extend behavior of this element.
61     *
62     * @return {@code null} by default
63     */
64    public Object getValue() {
65        return null;
66    }
67
68    /**
69     * Returns {@code void} state of this value object.
70     *
71     * @return {@code false} always
72     */
73    public final boolean isVoid() {
74        return false;
75    }
76}
77