Java example source code file (JAXBIntrospector.java)

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Java - Java tags/keywords

jaxbelement, jaxbintrospector, object, qname

The JAXBIntrospector.java Java example source code

/*
 * Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.xml.bind;
import  javax.xml.namespace.QName;

/**
 * Provide access to JAXB xml binding data for a JAXB object.
 *
 * <p>
 * Intially, the intent of this class is to just conceptualize how
 * a JAXB application developer can access xml binding information,
 * independent if binding model is java to schema or schema to java.
 * Since accessing the XML element name related to a JAXB element is
 * a highly requested feature, demonstrate access to this
 * binding information.
 *
 * The factory method to get a <code>JAXBIntrospector instance is
 * {@link JAXBContext#createJAXBIntrospector()}.
 *
 * @see JAXBContext#createJAXBIntrospector()
 * @since JAXB2.0
 */
public abstract class JAXBIntrospector {

    /**
     * <p>Return true if object represents a JAXB element.

     * <p>Parameter object is a JAXB element for following cases:
     * <ol>
     *   <li>It is an instance of javax.xml.bind.JAXBElement.
     *   <li>The class of object is annotated with
     *       <code>@XmlRootElement.
     *   </li>
     * </ol>
     *
     * @see #getElementName(Object)
     */
    public abstract boolean isElement(Object object);

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

     *
     * @param jaxbElement is an object that {@link #isElement(Object)} returned true.
     *
     * @return xml element qname associated with jaxbElement;
     *         null if <code>jaxbElement is not a JAXB Element.
     */
    public abstract QName getElementName(Object jaxbElement);

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

     *
     * <p>Convenience method to abstract whether working with either
     *    a javax.xml.bind.JAXBElement instance or an instance of
     *    <tt>@XmlRootElement annotated Java class.

     *
     * @param jaxbElement  object that #isElement(Object) returns true.
     *
     * @return The element value of the <code>jaxbElement.
     */
    public static Object getValue(Object jaxbElement) {
        if (jaxbElement instanceof JAXBElement) {
            return ((JAXBElement)jaxbElement).getValue();
        } else {
            // assume that class of this instance is
            // annotated with @XmlRootElement.
            return jaxbElement;
        }
    }
}