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javax.xml.bind.annotation
public class: XmlRootElement [javadoc | source]
javax.xml.bind.annotation.XmlRootElement
Maps a class or an enum type to an XML element.

Usage

The @XmlRootElement annotation can be used with the following program elements:

See "Package Specification" in javax.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>
Method from javax.xml.bind.annotation.XmlRootElement Summary:
name,   namespace
Method from javax.xml.bind.annotation.XmlRootElement Detail:
 String name() 
    local name of the XML element.

    If the value is "##default", then the name is derived from the class name.

 String namespace() 
    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.