/*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.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.
*
* <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><xmp>
* <!-- 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"/>
* </xmp></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><xmp>
* <!-- 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>
* </xmp></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 JAXB 2.0
*/
@Retention(RUNTIME)
@Target({METHOD})
public @interface XmlElementDecl {
/**
* 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.
* <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.
*
* <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.
* <p>
* This specifies the namespace name of the XML element whose local
* name is specified by <tt>substitutionHeadName()</tt>.
* <p>
* If <tt>susbtitutionHeadName()</tt> 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 <tt>susbstitutionHeadName()</tt> is "".
* <p>
* If <tt>susbtitutionHeadName()</tt> 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 <tt>susbtitutionHeadName()</tt> 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.
* <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.
*
* <p>
* 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.
*/
String defaultValue() default "\u0000";
/**
* Used in {@link XmlElementDecl#scope()} to
* signal that the declaration is in the global scope.
*/
public final class GLOBAL {}
}
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