This annotation serves as a "catch-all" property while unmarshalling xml content into an instance of a Jakarta XML Binding annotated class. It typically annotates a multivalued 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;
}
<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>
<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:complexContent>
</xs:complexType>
class Bar extends Foo {
int c;
// Foo.getAny() also represents wildcard content for type definition bar.
}
<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 XmlElementRef
s 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 ) { ... }
}
<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;
}
<foo>
<unknown />
<foo />
</foo>
Foo foo = unmarshal();
// 1 for 'unknown', another for 'foo'
assert foo.others.length==2;
// 'unknown' unmarshalls to a DOM element
assert foo.others[0] instanceof Element;
// because of lax=true, the 'foo' element eagerly
// unmarshalls to a Foo object.
assert foo.others[1] instanceof Foo;
- Author:
- Kohsuke Kawaguchi
-
Optional Element Summary
Modifier and TypeOptional ElementDescriptionboolean
Controls the unmarshaller behavior when it sees elements known to the currentJAXBContext
.Class
<? extends DomHandler<?, ?>> Specifies theDomHandler
which is responsible for actually converting XML from/to a DOM-like data structure.
-
Element Details
-
lax
boolean laxControls the unmarshaller behavior when it sees elements known to the currentJAXBContext
.- 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 toJAXBContext
(for example, there's a class withXmlRootElement
that has the same tag name, or there'sXmlElementDecl
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 unmarshalls the element to aJAXBElement
, 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
Class<? extends DomHandler<?,?>> valueSpecifies theDomHandler
which is responsible for actually converting XML from/to a DOM-like data structure.- Default:
jakarta.xml.bind.annotation.W3CDomHandler.class
-