01 /*
02 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
03 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
04 *
05 * This code is free software; you can redistribute it and/or modify it
06 * under the terms of the GNU General Public License version 2 only, as
07 * published by the Free Software Foundation. Sun designates this
08 * particular file as subject to the "Classpath" exception as provided
09 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package javax.xml.bind;
27
28 import javax.xml.namespace.QName;
29
30 /**
31 * Provide access to JAXB xml binding data for a JAXB object.
32 *
33 * <p>
34 * Intially, the intent of this class is to just conceptualize how
35 * a JAXB application developer can access xml binding information,
36 * independent if binding model is java to schema or schema to java.
37 * Since accessing the XML element name related to a JAXB element is
38 * a highly requested feature, demonstrate access to this
39 * binding information.
40 *
41 * The factory method to get a <code>JAXBIntrospector</code> instance is
42 * {@link JAXBContext#createJAXBIntrospector()}.
43 *
44 * @see JAXBContext#createJAXBIntrospector()
45 * @since JAXB2.0
46 */
47 public abstract class JAXBIntrospector {
48
49 /**
50 * <p>Return true iff <code>object</code> represents a JAXB element.</p>
51 * <p>Parameter <code>object</code> is a JAXB element for following cases:
52 * <ol>
53 * <li>It is an instance of <code>javax.xml.bind.JAXBElement</code>.</li>
54 * <li>The class of <code>object</code> is annotated with
55 * <code>@XmlRootElement</code>.
56 * </li>
57 * </ol>
58 *
59 * @see #getElementName(Object)
60 */
61 public abstract boolean isElement(Object object);
62
63 /**
64 * <p>Get xml element qname for <code>jaxbElement</code>.</p>
65 *
66 * @param jaxbElement is an object that {@link #isElement(Object)} returned true.
67 *
68 * @return xml element qname associated with jaxbElement;
69 * null if <code>jaxbElement</code> is not a JAXB Element.
70 */
71 public abstract QName getElementName(Object jaxbElement);
72
73 /**
74 * <p>Get the element value of a JAXB element.</p>
75 *
76 * <p>Convenience method to abstract whether working with either
77 * a javax.xml.bind.JAXBElement instance or an instance of
78 * <tt>@XmlRootElement</tt> annotated Java class.</p>
79 *
80 * @param jaxbElement object that #isElement(Object) returns true.
81 *
82 * @return The element value of the <code>jaxbElement</code>.
83 */
84 public static Object getValue(Object jaxbElement) {
85 if (jaxbElement instanceof JAXBElement) {
86 return ((JAXBElement) jaxbElement).getValue();
87 } else {
88 // assume that class of this instance is
89 // annotated with @XmlRootElement.
90 return jaxbElement;
91 }
92 }
93 }
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