- Roman Grigoriadi (Oracle Corporation)
/*
* Copyright (c) 2004, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package jakarta.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.
Usage
The @XmlRootElement annotation can be used with the following program
elements:
- a top level class
- an enum type
See "Package Specification" in jakarta.xml.bind.package javadoc for
additional common information.
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.
This annotation can be used with the following annotations: XmlType, XmlEnum, XmlAccessorType, XmlAccessorOrder.
Example 1: Associate an element with XML Schema type
// Example: Code fragment
@XmlRootElement
class Point {
int x;
int y;
Point(int _x,int _y) {x=_x;y=_y;}
}
//Example: Code fragment corresponding to XML output
marshal( new Point(3,5), System.out);
<!-- Example: XML output -->
<point>
<x> 3 </x>
<y> 5 </y>
</point>
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.
<!-- 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>
Example 2: Orthogonality to type inheritance
An element declaration annotated on a type is not inherited by its
derived types. The following example shows this.
// 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>
Example 3: Associate a global element with XML Schema type
to which the class is mapped.
//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>
Author: Sekhar Vajjhala, Sun Microsystems, Inc. Since: 1.6, JAXB 2.0
/**
* Maps a class or an enum type to an XML element.
*
* <p> <b>Usage</b> </p>
* <p>
* The @XmlRootElement annotation can be used with the following program
* elements:
* <ul>
* <li> a top level class </li>
* <li> an enum type </li>
* </ul>
*
* <p>See "Package Specification" in jakarta.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: </b> 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>{@code
*
* <!-- 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>{@code
*
* <!-- 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 </b>
*
* <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 );
* {@code
*
* <!-- 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: </b> 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;
* }
* {@code
*
* <!-- 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 1.6, JAXB 2.0
*/
@Retention(RUNTIME)
@Target({TYPE})
public @interface XmlRootElement {
namespace name of the XML element.
If the value is "##default", then the XML namespace name is derived from the package of the class ( XmlSchema ). If the package is unnamed, then the XML namespace is the default empty namespace.
/**
* 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.
If the value is "##default", then the name is derived from the
class name.
/**
* 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";
}