1 /*
   2  * Copyright (c) 2004, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.xml.bind.annotation;
  27 
  28 import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
  29 import static java.lang.annotation.RetentionPolicy.RUNTIME;
  30 import static java.lang.annotation.ElementType.FIELD;
  31 import static java.lang.annotation.ElementType.METHOD;
  32 import java.lang.annotation.Retention;
  33 import java.lang.annotation.Target;
  34 
  35 /**
  36  * <p>
  37  * A container for multiple @{@link XmlElement} annotations.
  38  *
  39  * Multiple annotations of the same type are not allowed on a program
  40  * element. This annotation therefore serves as a container annotation
  41  * for multiple @XmlElements as follows:
  42  *
  43  * <pre>
  44  * @XmlElements({ @XmlElement(...),@XmlElement(...) })
  45  * </pre>
  46  *
  47  * <p>The <tt>@XmlElements</tt> annnotation can be used with the
  48  * following program elements: </p>
  49  * <ul>
  50  *   <li> a JavaBean property </li>
  51  *   <li> non static, non transient field </li>
  52  * </ul>
  53  *
  54  * This annotation is intended for annotation a JavaBean collection
  55  * property (e.g. List).
  56  *
  57  * <p><b>Usage</b></p>
  58  *
  59  * <p>The usage is subject to the following constraints:
  60  * <ul>
  61  *   <li> This annotation can be used with the following
  62  *        annotations: @{@link XmlIDREF}, @{@link XmlElementWrapper}. </li>
  63  *   <li> If @XmlIDREF is also specified on the JavaBean property,
  64  *        then each @XmlElement.type() must contain a JavaBean
  65  *        property annotated with <tt>@XmlID</tt>.</li>
  66  * </ul>
  67  *
  68  * <p>See "Package Specification" in javax.xml.bind.package javadoc for
  69  * additional common information.</p>
  70  *
  71  * <hr>
  72  *
  73  * <p><b>Example 1:</b> Map to a list of elements</p>
  74  * <pre>
  75  *
  76  *    // Mapped code fragment
  77  *    public class Foo {
  78  *        @XmlElements(
  79  *            @XmlElement(name="A", type=Integer.class),
  80  *            @XmlElement(name="B", type=Float.class)
  81  *         }
  82  *         public List items;
  83  *    }
  84  *
  85  *    &lt;!-- XML Representation for a List of {1,2.5}
  86  *            XML output is not wrapped using another element -->
  87  *    ...
  88  *    &lt;A> 1 &lt;/A>
  89  *    &lt;B> 2.5 &lt;/B>
  90  *    ...
  91  *
  92  *    &lt;!-- XML Schema fragment -->
  93  *    &lt;xs:complexType name="Foo">
  94  *      &lt;xs:sequence>
  95  *        &lt;xs:choice minOccurs="0" maxOccurs="unbounded">
  96  *          &lt;xs:element name="A" type="xs:int"/>
  97  *          &lt;xs:element name="B" type="xs:float"/>
  98  *        &lt;xs:choice>
  99  *      &lt;/xs:sequence>
 100  *    &lt;/xs:complexType>
 101  *
 102  * </pre>
 103  *
 104  * <p><b>Example 2:</b> Map to a list of elements wrapped with another element
 105  * </p>
 106  * <pre>
 107  *
 108  *    // Mapped code fragment
 109  *    public class Foo {
 110  *        @XmlElementWrapper(name="bar")
 111  *        @XmlElements(
 112  *            @XmlElement(name="A", type=Integer.class),
 113  *            @XmlElement(name="B", type=Float.class)
 114  *        }
 115  *        public List items;
 116  *    }
 117  *
 118  *    &lt;!-- XML Schema fragment -->
 119  *    &lt;xs:complexType name="Foo">
 120  *      &lt;xs:sequence>
 121  *        &lt;xs:element name="bar">
 122  *          &lt;xs:complexType>
 123  *            &lt;xs:choice minOccurs="0" maxOccurs="unbounded">
 124  *              &lt;xs:element name="A" type="xs:int"/>
 125  *              &lt;xs:element name="B" type="xs:float"/>
 126  *            &lt;/xs:choice>
 127  *          &lt;/xs:complexType>
 128  *        &lt;/xs:element>
 129  *      &lt;/xs:sequence>
 130  *    &lt;/xs:complexType>
 131  * </pre>
 132  *
 133  * <p><b>Example 3:</b> Change element name based on type using an adapter.
 134  * </p>
 135  * <pre>
 136  *    class Foo {
 137  *       @XmlJavaTypeAdapter(QtoPAdapter.class)
 138  *       @XmlElements({
 139  *           @XmlElement(name="A",type=PX.class),
 140  *           @XmlElement(name="B",type=PY.class)
 141  *       })
 142  *       Q bar;
 143  *    }
 144  *
 145  *    @XmlType abstract class P {...}
 146  *    @XmlType(name="PX") class PX extends P {...}
 147  *    @XmlType(name="PY") class PY extends P {...}
 148  *
 149  *    &lt;!-- XML Schema fragment -->
 150  *    &lt;xs:complexType name="Foo">
 151  *      &lt;xs:sequence>
 152  *        &lt;xs:element name="bar">
 153  *          &lt;xs:complexType>
 154  *            &lt;xs:choice minOccurs="0" maxOccurs="unbounded">
 155  *              &lt;xs:element name="A" type="PX"/>
 156  *              &lt;xs:element name="B" type="PY"/>
 157  *            &lt;/xs:choice>
 158  *          &lt;/xs:complexType>
 159  *        &lt;/xs:element>
 160  *      &lt;/xs:sequence>
 161  *    &lt;/xs:complexType>
 162  * </pre>
 163  *
 164  * @author <ul><li>Kohsuke Kawaguchi, Sun Microsystems, Inc.</li><li>Sekhar Vajjhala, Sun Microsystems, Inc.</li></ul>
 165  * @see XmlElement
 166  * @see XmlElementRef
 167  * @see XmlElementRefs
 168  * @see XmlJavaTypeAdapter
 169  * @since 1.6, JAXB 2.0
 170  */
 171 @Retention(RUNTIME) @Target({FIELD,METHOD})
 172 public @interface XmlElements {
 173     /**
 174      * Collection of @{@link XmlElement} annotations
 175      */
 176     XmlElement[] value();
 177 }