- 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.METHOD;
Maps a factory method to a XML element.
Usage
The annotation creates a mapping between an XML schema element
declaration and a element factory method that returns a
JAXBElement instance representing the element
declaration. Typically, the element factory method is generated
(and annotated) from a schema into the ObjectFactory class in a
Java package that represents the binding of the element
declaration's target namespace. Thus, while the annotation syntax
allows @XmlElementDecl to be used on any method, semantically
its use is restricted to annotation of element factory method.
The usage is subject to the following constraints:
- The class containing the element factory method annotated with @XmlElementDecl must be marked with
XmlRegistry.
- The element factory method must take one parameter assignable to
Object.
Example 1: Annotation on a factory method
// Example: code fragment
@XmlRegistry
class ObjectFactory {
@XmlElementDecl(name="foo")
JAXBElement<String> createFoo(String s) { ... }
}
<!-- XML input -->
<foo>string</foo>
// Example: code fragment corresponding to XML input
JAXBElement<String> o =
(JAXBElement<String>)unmarshaller.unmarshal(aboveDocument);
// print JAXBElement instance to show values
System.out.println(o.getName()); // prints "{}foo"
System.out.println(o.getValue()); // prints "string"
System.out.println(o.getValue().getClass()); // prints "java.lang.String"
<!-- Example: XML schema definition -->
<xs:element name="foo" type="xs:string"/>
Example 2: Element declaration with non local scope
The following example illustrates the use of scope annotation
parameter in binding of element declaration in schema derived
code.
The following example may be replaced in a future revision of
this javadoc.
<!-- Example: XML schema definition -->
<xs:schema>
<xs:complexType name="pea">
<xs:choice maxOccurs="unbounded">
<xs:element name="foo" type="xs:string"/>
<xs:element name="bar" type="xs:string"/>
</xs:choice>
</xs:complexType>
<xs:element name="foo" type="xs:int"/>
</xs:schema>
// Example: expected default binding
class Pea {
@XmlElementRefs({
@XmlElementRef(name="foo",type=JAXBElement.class)
@XmlElementRef(name="bar",type=JAXBElement.class)
})
List<JAXBElement<String>> fooOrBar;
}
@XmlRegistry
class ObjectFactory {
@XmlElementDecl(scope=Pea.class,name="foo")
JAXBElement<String> createPeaFoo(String s);
@XmlElementDecl(scope=Pea.class,name="bar")
JAXBElement<String> createPeaBar(String s);
@XmlElementDecl(name="foo")
JAXBElement<Integer> createFoo(Integer i);
}
Without scope createFoo and createPeaFoo would become ambiguous
since both of them map to a XML schema element with the same local
name "foo".
See Also: Since: 1.6, JAXB 2.0
/**
* Maps a factory method to a XML element.
*
* <p> <b>Usage</b> </p>
*
* The annotation creates a mapping between an XML schema element
* declaration and a <i> element factory method </i> that returns a
* JAXBElement instance representing the element
* declaration. Typically, the element factory method is generated
* (and annotated) from a schema into the ObjectFactory class in a
* Java package that represents the binding of the element
* declaration's target namespace. Thus, while the annotation syntax
* allows @XmlElementDecl to be used on any method, semantically
* its use is restricted to annotation of element factory method.
*
* The usage is subject to the following constraints:
*
* <ul>
* <li> The class containing the element factory method annotated
* with @XmlElementDecl must be marked with {@link
* XmlRegistry}. </li>
* <li> The element factory method must take one parameter
* assignable to {@link Object}.</li>
* </ul>
*
* <p><b>Example 1: </b>Annotation on a factory method
* <pre>
* // Example: code fragment
* @XmlRegistry
* class ObjectFactory {
* @XmlElementDecl(name="foo")
* JAXBElement<String> createFoo(String s) { ... }
* }
* </pre>
* <pre> {@code
*
* <!-- XML input -->
* <foo>string</foo>
*
* // Example: code fragment corresponding to XML input
* JAXBElement<String> o =
* (JAXBElement<String>)unmarshaller.unmarshal(aboveDocument);
* // print JAXBElement instance to show values
* System.out.println(o.getName()); // prints "{}foo"
* System.out.println(o.getValue()); // prints "string"
* System.out.println(o.getValue().getClass()); // prints "java.lang.String"
*
* <!-- Example: XML schema definition -->
* <xs:element name="foo" type="xs:string"/>
* }</pre>
*
* <p><b>Example 2: </b> Element declaration with non local scope
* <p>
* The following example illustrates the use of scope annotation
* parameter in binding of element declaration in schema derived
* code.
* <p>
* The following example may be replaced in a future revision of
* this javadoc.
*
* <pre>{@code
* <!-- Example: XML schema definition -->
* <xs:schema>
* <xs:complexType name="pea">
* <xs:choice maxOccurs="unbounded">
* <xs:element name="foo" type="xs:string"/>
* <xs:element name="bar" type="xs:string"/>
* </xs:choice>
* </xs:complexType>
* <xs:element name="foo" type="xs:int"/>
* </xs:schema>
* }</pre>
* <pre>
* // Example: expected default binding
* class Pea {
* @XmlElementRefs({
* @XmlElementRef(name="foo",type=JAXBElement.class)
* @XmlElementRef(name="bar",type=JAXBElement.class)
* })
* List<JAXBElement<String>> fooOrBar;
* }
*
* @XmlRegistry
* class ObjectFactory {
* @XmlElementDecl(scope=Pea.class,name="foo")
* JAXBElement<String> createPeaFoo(String s);
*
* @XmlElementDecl(scope=Pea.class,name="bar")
* JAXBElement<String> createPeaBar(String s);
*
* @XmlElementDecl(name="foo")
* JAXBElement<Integer> createFoo(Integer i);
* }
*
* </pre>
* Without scope createFoo and createPeaFoo would become ambiguous
* since both of them map to a XML schema element with the same local
* name "foo".
*
* @see XmlRegistry
* @since 1.6, JAXB 2.0
*/
@Retention(RUNTIME)
@Target({METHOD})
public @interface XmlElementDecl {
scope of the mapping.
If this is not GLOBAL, then this element declaration mapping is only active within the specified class.
/**
* scope of the mapping.
*
* <p>
* If this is not {@link XmlElementDecl.GLOBAL}, then this element
* declaration mapping is only active within the specified class.
*/
Class scope() default GLOBAL.class;
namespace name of the XML element.
If the value is "##default", then the value is the namespace
name for the package of the class containing this factory method.
See Also: - name()
/**
* namespace name of the XML element.
* <p>
* If the value is "##default", then the value is the namespace
* name for the package of the class containing this factory method.
*
* @see #name()
*/
String namespace() default "##default";
local name of the XML element.
Note to reviewers: There is no default name; since
the annotation is on a factory method, it is not clear that the
method name can be derived from the factory method name.
See Also: - namespace()
/**
* local name of the XML element.
*
* <p>
* <b> Note to reviewers: </b> There is no default name; since
* the annotation is on a factory method, it is not clear that the
* method name can be derived from the factory method name.
* @see #namespace()
*/
String name();
namespace name of a substitution group's head XML element.
This specifies the namespace name of the XML element whose local name is specified by substitutionHeadName().
If susbtitutionHeadName() is "", then this value can only be "##default". But the value is ignored since since this element is not part of susbtitution group when the value of susbstitutionHeadName() is "".
If susbtitutionHeadName() is not "" and the value is "##default", then the namespace name is the namespace name to which the package of the containing class, marked with XmlRegistry, is mapped.
If susbtitutionHeadName() is not "" and the value is not "##default", then the value is the namespace name.
See Also:
/**
* namespace name of a substitution group's head XML element.
* <p>
* This specifies the namespace name of the XML element whose local
* name is specified by {@code substitutionHeadName()}.
* <p>
* If {@code susbtitutionHeadName()} is "", then this
* value can only be "##default". But the value is ignored since
* since this element is not part of susbtitution group when the
* value of {@code susbstitutionHeadName()} is "".
* <p>
* If {@code susbtitutionHeadName()} is not "" and the value is
* "##default", then the namespace name is the namespace name to
* which the package of the containing class, marked with {@link
* XmlRegistry }, is mapped.
* <p>
* If {@code susbtitutionHeadName()} is not "" and the value is
* not "##default", then the value is the namespace name.
*
* @see #substitutionHeadName()
*/
String substitutionHeadNamespace() default "##default";
XML local name of a substitution group's head element.
If the value is "", then this element is not part of any
substitution group.
See Also: - substitutionHeadNamespace()
/**
* XML local name of a substitution group's head element.
* <p>
* If the value is "", then this element is not part of any
* substitution group.
*
* @see #substitutionHeadNamespace()
*/
String substitutionHeadName() default "";
Default value of this element.
The
'\u0000'
value specified as a default of this annotation element
is used as a poor-man's substitute for null to allow implementations
to recognize the 'no default value' state.
/**
* Default value of this element.
*
* <p>
* The <pre>'\u0000'</pre> value specified as a default of this annotation element
* is used as a poor-man's substitute for null to allow implementations
* to recognize the 'no default value' state.
*/
String defaultValue() default "\u0000";
Used in XmlElementDecl.scope() to signal that the declaration is in the global scope. /**
* Used in {@link XmlElementDecl#scope()} to
* signal that the declaration is in the global scope.
*/
public final class GLOBAL {}
}