Java example source code file (XmlRootElement.java)

This example Java source code file (XmlRootElement.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

annotation, retention, string, target, type, xmlrootelement

The XmlRootElement.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.annotation;

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.RetentionPolicy.RUNTIME;
import static java.lang.annotation.ElementType.TYPE;

/**
 * Maps a class or an enum type to an XML element.
 *
 * <p> Usage 

 * <p>
 * The @XmlRootElement annotation can be used with the following program
 * elements:
 * <ul>
 *   <li> a top level class 
 *   <li> an enum type 
 * </ul>
 *
 * <p>See "Package Specification" in javax.xml.bind.package javadoc for
 * additional common information.</p>
 *
 * <p>
 * When a top level class or an enum type is annotated with the
 * @XmlRootElement annotation, then its value is represented
 * as XML element in an XML document.
 *
 * <p> This annotation can be used with the following annotations:
 * {@link XmlType}, {@link XmlEnum}, {@link XmlAccessorType},
 * {@link XmlAccessorOrder}.
 * <p>

 * <p>
 * <b>Example 1:  Associate an element with XML Schema type
 * <pre>
 *     // Example: Code fragment
 *     @XmlRootElement
 *     class Point {
 *        int x;
 *        int y;
 *        Point(int _x,int _y) {x=_x;y=_y;}
 *     }
 * </pre>
 *
 * <pre>
 *     //Example: Code fragment corresponding to XML output
 *     marshal( new Point(3,5), System.out);
 * </pre>
 *
 * <pre>
 *     <!-- Example: XML output -->
 *     <point>
 *       <x> 3 </x>
 *       <y> 5 </y>
 *     </point>
 * </pre>
 *
 * The annotation causes an global element declaration to be produced
 * in the schema. The global element declaration is associated with
 * the XML schema type to which the class is mapped.
 *
 * <pre>
 *     <!-- Example: XML schema definition -->
 *     <xs:element name="point" type="point"/>
 *     <xs:complexType name="point">
 *       <xs:sequence>
 *         <xs:element name="x" type="xs:int"/>
 *         <xs:element name="y" type="xs:int"/>
 *       </xs:sequence>
 *     </xs:complexType>
 * </pre>
 *
 * <p>
 *
 * <b>Example 2: Orthogonality to type inheritance 
 *
 * <p>
 * An element declaration annotated on a type is not inherited by its
 * derived types. The following example shows this.
 * <pre>
 *     // Example: Code fragment
 *     @XmlRootElement
 *     class Point3D extends Point {
 *         int z;
 *         Point3D(int _x,int _y,int _z) {super(_x,_y);z=_z;}
 *     }
 *
 *     //Example: Code fragment corresponding to XML output *
 *     marshal( new Point3D(3,5,0), System.out );
 *
 *     <!-- Example: XML output -->
 *     <!-- The element name is point3D not point -->
 *     <point3D>
 *       <x>3</x>
 *       <y>5</y>
 *       <z>0</z>
 *     </point3D>
 *
 *     <!-- Example: XML schema definition -->
 *     <xs:element name="point3D" type="point3D"/>
 *     <xs:complexType name="point3D">
 *       <xs:complexContent>
 *         <xs:extension base="point">
 *           <xs:sequence>
 *             <xs:element name="z" type="xs:int"/>
 *           </xs:sequence>
 *         </xs:extension>
 *       </xs:complexContent>
 *     </xs:complexType>
 * </pre>
 *
 * <b>Example 3:  Associate a global element with XML Schema type
 * to which the class is mapped.
 * <pre>
 *     //Example: Code fragment
 *     @XmlRootElement(name="PriceElement")
 *     public class USPrice {
 *         @XmlElement
 *         public java.math.BigDecimal price;
 *     }
 *
 *     <!-- Example: XML schema definition -->
 *     <xs:element name="PriceElement" type="USPrice"/>
 *     <xs:complexType name="USPrice">
 *       <xs:sequence>
 *         <xs:element name="price" type="xs:decimal"/>
 *       </sequence>
 *     </xs:complexType>
 * </pre>
 *
 * @author Sekhar Vajjhala, Sun Microsystems, Inc.
 * @since JAXB2.0
 */
@Retention(RUNTIME)
@Target({TYPE})
public @interface XmlRootElement {
    /**
     * namespace name of the XML element.
     * <p>
     * If the value is "##default", then the XML namespace name is derived
     * from the package of the class ( {@link XmlSchema} ). If the
     * package is unnamed, then the XML namespace is the default empty
     * namespace.
     */
    String namespace() default "##default";

    /**
     * local name of the XML element.
     * <p>
     * If the value is "##default", then the name is derived from the
     * class name.
     *
     */
    String name() default "##default";

}