Module jakarta.xml.bind

Package jakarta.xml.bind.annotation

Annotation Type XmlAnyElement

@Retention(RUNTIME)
@Target({FIELD,METHOD})
public @interface XmlAnyElement

Maps a JavaBean property to XML infoset representation and/or JAXBElement.

This annotation serves as a "catch-all" property while unmarshalling xml content into a instance of a Jakarta XML Binding annotated class. It typically annotates a multi-valued JavaBean property, but it can occur on single value JavaBean property. During unmarshalling, each xml element that does not match a static @XmlElement or @XmlElementRef annotation for the other JavaBean properties on the class, is added to this "catch-all" property.

Usages:

 @XmlAnyElement
 public Element[] others;

 // Collection of Element or JAXBElements.
 @XmlAnyElement(lax="true")
 public Object[] others;

 @XmlAnyElement
 private List<Element> nodes;

 @XmlAnyElement
 private Element node;
 

Restriction usage constraints

This annotation is mutually exclusive with XmlElement, XmlAttribute, XmlValue, XmlElements, XmlID, and XmlIDREF.

There can be only one XmlAnyElement annotated JavaBean property in a class and its super classes.

Relationship to other annotations

This annotation can be used with XmlJavaTypeAdapter, so that users can map their own data structure to DOM, which in turn can be composed into XML.

This annotation can be used with XmlMixed like this:

 // List of java.lang.String or DOM nodes.
 @XmlAnyElement @XmlMixed
 List<Object> others;
 

Schema To Java example

The following schema would produce the following Java class:

 <xs:complexType name="foo">
   <xs:sequence>
     <xs:element name="a" type="xs:int" />
     <xs:element name="b" type="xs:int" />
     <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded" />
   </xs:sequence>
 </xs:complexType>
 

 class Foo {
   int a;
   int b;
   @XmlAnyElement
   List<Element> any;
 }
 

It can unmarshal instances like

 <foo xmlns:e="extra">
   <a>1</a>
   <e:other />  // this will be bound to DOM, because unmarshalling is orderless
   <b>3</b>
   <e:other />
   <c>5</c>     // this will be bound to DOM, because the annotation doesn't remember namespaces.
 </foo>
 

The following schema would produce the following Java class:

 <xs:complexType name="bar">
   <xs:complexContent>
   <xs:extension base="foo">
     <xs:sequence>
       <xs:element name="c" type="xs:int" />
       <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded" />
     </xs:sequence>
   </xs:extension>
 </xs:complexType>
 

 class Bar extends Foo {
   int c;
   // Foo.getAny() also represents wildcard content for type definition bar.
 }
 

It can unmarshal instances like

 <bar xmlns:e="extra">
   <a>1</a>
   <e:other />  // this will be bound to DOM, because unmarshalling is orderless
   <b>3</b>
   <e:other />
   <c>5</c>     // this now goes to Bar.c
   <e:other />  // this will go to Foo.any
 </bar>
 

Using XmlAnyElement with XmlElementRef

The XmlAnyElement annotation can be used with XmlElementRefs to designate additional elements that can participate in the content tree.

The following schema would produce the following Java class:

 <xs:complexType name="foo">
   <xs:choice maxOccurs="unbounded" minOccurs="0">
     <xs:element name="a" type="xs:int" />
     <xs:element name="b" type="xs:int" />
     <xs:any namespace="##other" processContents="lax" />
   </xs:choice>
 </xs:complexType>
 

 class Foo {
   @XmlAnyElement(lax="true")
   @XmlElementRefs({
     @XmlElementRef(name="a", type="JAXBElement.class")
     @XmlElementRef(name="b", type="JAXBElement.class")
   })
   List<Object> others;
 }

 @XmlRegistry
 class ObjectFactory {
   ...
   @XmlElementDecl(name = "a", namespace = "", scope = Foo.class)
   JAXBElement<Integer> createFooA( Integer i ) { ... }

   @XmlElementDecl(name = "b", namespace = "", scope = Foo.class)
   JAXBElement<Integer> createFooB( Integer i ) { ... }
 

It can unmarshal instances like

<foo xmlns:e="extra">
  <a>1</a>     // this will unmarshal to a JAXBElement instance whose value is 1.
  <e:other />  // this will unmarshal to a DOM Element.
  <b>3</b>     // this will unmarshal to a JAXBElement instance whose value is 1.
</foo>
 

W3C XML Schema "lax" wildcard emulation

The lax element of the annotation enables the emulation of the "lax" wildcard semantics. For example, when the Java source code is annotated like this:

 @XmlRootElement
 class Foo {
   @XmlAnyElement(lax=true)
   public Object[] others;
 }
 

then the following document will unmarshal like this:

 <foo>
   <unknown />
   <foo />
 </foo>

 Foo foo = unmarshal();
 // 1 for 'unknown', another for 'foo'
 assert foo.others.length==2;
 // 'unknown' unmarshals to a DOM element
 assert foo.others[0] instanceof Element;
 // because of lax=true, the 'foo' element eagerly
 // unmarshals to a Foo object.
 assert foo.others[1] instanceof Foo;
 

Author:

Kohsuke Kawaguchi

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
boolean	lax	Controls the unmarshaller behavior when it sees elements known to the current JAXBContext.
java.lang.Class<? extends DomHandler<?,?>>	value	Specifies the DomHandler which is responsible for actually converting XML from/to a DOM-like data structure.

Element Detail

lax

boolean lax

Controls the unmarshaller behavior when it sees elements known to the current JAXBContext.

When false

If false, all the elements that match the property will be unmarshalled to DOM, and the property will only contain DOM elements.

When true

If true, when an element matches a property marked with XmlAnyElement is known to JAXBContext (for example, there's a class with XmlRootElement that has the same tag name, or there's XmlElementDecl that has the same tag name), the unmarshaller will eagerly unmarshal this element to the Jakarta XML Binding object, instead of unmarshalling it to DOM. Additionally, if the element is unknown but it has a known xsi:type, the unmarshaller eagerly unmarshals the element to a JAXBElement, with the unknown element name and the JAXBElement value is set to an instance of the Jakarta XML Binding mapping of the known xsi:type.

As a result, after the unmarshalling, the property can become heterogeneous; it can have both DOM nodes and some Jakarta XML Binding objects at the same time.

This can be used to emulate the "lax" wildcard semantics of the W3C XML Schema.

Default:

false

value

java.lang.Class<? extends DomHandler<?,?>> value

Specifies the DomHandler which is responsible for actually converting XML from/to a DOM-like data structure.

Default:

jakarta.xml.bind.annotation.W3CDomHandler.class