1 /*

     2  * Copyright (c) 2004, 2010, 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  */

    25 

    26 package javax.xml.bind;

    27 import  javax.xml.namespace.QName;

    28 

    29 /**

    30  * Provide access to JAXB xml binding data for a JAXB object.

    31  *

    32  * <p>

    33  * Intially, the intent of this class is to just conceptualize how

    34  * a JAXB application developer can access xml binding information,

    35  * independent if binding model is java to schema or schema to java.

    36  * Since accessing the XML element name related to a JAXB element is

    37  * a highly requested feature, demonstrate access to this

    38  * binding information.

    39  *

    40  * The factory method to get a <code>JAXBIntrospector</code> instance is

    41  * {@link JAXBContext#createJAXBIntrospector()}.

    42  *

    43  * @see JAXBContext#createJAXBIntrospector()

    44  * @since JAXB2.0

    45  */

    46 public abstract class JAXBIntrospector {

    47 

    48     /**

    49      * <p>Return true iff <code>object</code> represents a JAXB element.</p>

    50      * <p>Parameter <code>object</code> is a JAXB element for following cases:

    51      * <ol>

    52      *   <li>It is an instance of <code>javax.xml.bind.JAXBElement</code>.</li>

    53      *   <li>The class of <code>object</code> is annotated with

    54      *       <code>&#64XmlRootElement</code>.

    55      *   </li>

    56      * </ol>

    57      *

    58      * @see #getElementName(Object)

    59      */

    60     public abstract boolean isElement(Object object);

    61 

    62     /**

    63      * <p>Get xml element qname for <code>jaxbElement</code>.</p>

    64      *

    65      * @param jaxbElement is an object that {@link #isElement(Object)} returned true.

    66      *

    67      * @return xml element qname associated with jaxbElement;

    68      *         null if <code>jaxbElement</code> is not a JAXB Element.

    69      */

    70     public abstract QName getElementName(Object jaxbElement);

    71 

    72     /**

    73      * <p>Get the element value of a JAXB element.</p>

    74      *

    75      * <p>Convenience method to abstract whether working with either

    76      *    a javax.xml.bind.JAXBElement instance or an instance of

    77      *    <tt>&#64XmlRootElement</tt> annotated Java class.</p>

    78      *

    79      * @param jaxbElement  object that #isElement(Object) returns true.

    80      *

    81      * @return The element value of the <code>jaxbElement</code>.

    82      */

    83     public static Object getValue(Object jaxbElement) {

    84         if (jaxbElement instanceof JAXBElement) {

    85             return ((JAXBElement)jaxbElement).getValue();

    86         } else {

    87             // assume that class of this instance is

    88             // annotated with @XmlRootElement.

    89             return jaxbElement;

    90         }

    91     }

    92 }