Java example source code file (XmlElement.java)

This example Java source code file (XmlElement.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

annotation, class, default, field, method, parameter, retention, string, target, xmlelement

The XmlElement.java Java example source code

/*
 * Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.xml.bind.annotation;

import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.RetentionPolicy.*;

/**
 * Maps a JavaBean property to a XML element derived from property name.
 *
 * <p> Usage 

 * <p>
 * <tt>@XmlElement annotation can be used with the following program
 * elements:
 * <ul>
 *   <li> a JavaBean property 
 *   <li> non static, non transient field 
 *   <li> within {@link XmlElements}
 * <p>
 *
 * </ul>
 *
 * The usage is subject to the following constraints:
 * <ul>
 *   <li> This annotation can be used with following annotations:
 *            {@link XmlID},
 *            {@link XmlIDREF},
 *            {@link XmlList},
 *            {@link XmlSchemaType},
 *            {@link XmlValue},
 *            {@link XmlAttachmentRef},
 *            {@link XmlMimeType},
 *            {@link XmlInlineBinaryData},
 *            {@link XmlElementWrapper},
 *            {@link XmlJavaTypeAdapter}</li>
 *   <li> if the type of JavaBean property is a collection type of
 *        array, an indexed property, or a parameterized list, and
 *        this annotation is used with {@link XmlElements} then,
 *        <tt>@XmlElement.type() must be DEFAULT.class since the
 *        collection item type is already known. </li>
 * </ul>
 *
 * <p>
 * A JavaBean property, when annotated with @XmlElement annotation
 * is mapped to a local element in the XML Schema complex type to
 * which the containing class is mapped.
 *
 * <p>
 * <b>Example 1:  Map a public non static non final field to local
 * element
 * <pre>
 *     //Example: Code fragment
 *     public class USPrice {
 *         @XmlElement(name="itemprice")
 *         public java.math.BigDecimal price;
 *     }
 *
 *     <!-- Example: Local XML Schema element -->
 *     <xs:complexType name="USPrice"/>
 *       <xs:sequence>
 *         <xs:element name="itemprice" type="xs:decimal" minOccurs="0"/>
 *       </sequence>
 *     </xs:complexType>
 *   </pre>
 * <p>
 *
 * <b> Example 2:  Map a field to a nillable element.
 *   <pre>
 *
 *     //Example: Code fragment
 *     public class USPrice {
 *         @XmlElement(nillable=true)
 *         public java.math.BigDecimal price;
 *     }
 *
 *     <!-- Example: Local XML Schema element -->
 *     <xs:complexType name="USPrice">
 *       <xs:sequence>
 *         <xs:element name="price" type="xs:decimal" nillable="true" minOccurs="0"/>
 *       </sequence>
 *     </xs:complexType>
 *   </pre>
 * <p>
 * <b> Example 3:  Map a field to a nillable, required element.
 *   <pre>
 *
 *     //Example: Code fragment
 *     public class USPrice {
 *         @XmlElement(nillable=true, required=true)
 *         public java.math.BigDecimal price;
 *     }
 *
 *     <!-- Example: Local XML Schema element -->
 *     <xs:complexType name="USPrice">
 *       <xs:sequence>
 *         <xs:element name="price" type="xs:decimal" nillable="true" minOccurs="1"/>
 *       </sequence>
 *     </xs:complexType>
 *   </pre>
 * <p>
 *
 * <p> Example 4: Map a JavaBean property to an XML element
 * with anonymous type.</p>
 * <p>
 * See Example 6 in @{@link XmlType}.
 *
 * <p>
 * @author Sekhar Vajjhala, Sun Microsystems, Inc.
 * @since JAXB2.0
 */

@Retention(RUNTIME) @Target({FIELD, METHOD, PARAMETER})
public @interface XmlElement {
    /**
     * Name of the XML Schema element.
     * <p> If the value is "##default", then element name is derived from the
     * JavaBean property name.
     */
    String name() default "##default";

    /**
     * Customize the element declaration to be nillable.
     * <p>If nillable() is true, then the JavaBean property is
     * mapped to a XML Schema nillable element declaration.
     */
    boolean nillable() default false;

    /**
     * Customize the element declaration to be required.
     * <p>If required() is true, then Javabean property is mapped to
     * an XML schema element declaration with minOccurs="1".
     * maxOccurs is "1" for a single valued property and "unbounded"
     * for a multivalued property.
     * <p>If required() is false, then the Javabean property is mapped
     * to XML Schema element declaration with minOccurs="0".
     * maxOccurs is "1" for a single valued property and "unbounded"
     * for a multivalued property.
     */

    boolean required() default false;

    /**
     * XML target namespace of the XML Schema element.
     * <p>
     * If the value is "##default", then the namespace is determined
     * as follows:
     * <ol>
     *  <li>
     *  If the enclosing package has {@link XmlSchema} annotation,
     *  and its {@link XmlSchema#elementFormDefault() elementFormDefault}
     *  is {@link XmlNsForm#QUALIFIED QUALIFIED}, then the namespace of
     *  the enclosing class.
     *
     *  <li>
     *  Otherwise '' (which produces unqualified element in the default
     *  namespace.
     * </ol>
     */
    String namespace() default "##default";

    /**
     * Default value of this element.
     *
     * <p>
     * The <pre>'\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"; /** * The Java class being referenced. */ Class type() default DEFAULT.class; /** * Used in {@link XmlElement#type()} to * signal that the type be inferred from the signature * of the property. */ static final class DEFAULT {} }