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 java.lang.annotation.Target;
  29 import java.lang.annotation.Retention;
  30 import static java.lang.annotation.ElementType.*;
  31 import static java.lang.annotation.RetentionPolicy.*;
  32 
  33 /**
  34  * <p>
  35  * Maps a JavaBean property to XML ID.
  36  *
  37  * <p>
  38  * To preserve referential integrity of an object graph across XML
  39  * serialization followed by a XML deserialization, requires an object
  40  * reference to be marshalled by reference or containment
  41  * appropriately. Annotations <tt>@XmlID</tt> and <tt>@XmlIDREF</tt>
  42  * together allow a customized mapping of a JavaBean property's
  43  * type by containment or reference.
  44  *
  45  * <p><b>Usage</b> </p>
  46  * The <tt>@XmlID</tt> annotation can be used with the following
  47  * program elements:
  48  * <ul>
  49  *   <li> a JavaBean property </li>
  50  *   <li> non static, non transient field </li>
  51  * </ul>
  52  *
  53  * <p>See "Package Specification" in javax.xml.bind.package javadoc for
  54  * additional common information.</p>
  55  *
  56  * The usage is subject to the following constraints:
  57  * <ul>
  58  *   <li> At most one field or property in a class can be annotated
  59  *        with <tt>@XmlID</tt>.  </li>
  60  *   <li> The JavaBean property's type must be <tt>java.lang.String</tt>.</li>
  61  *   <li> The only other mapping annotations that can be used
  62  *        with <tt>@XmlID</tt>
  63  *        are:<tt>@XmlElement</tt> and <tt>@XmlAttribute</tt>.</li>
  64  * </ul>
  65  *
  66  * <p><b>Example</b>: Map a JavaBean property's type to <tt>xs:ID</tt></p>
  67  * <pre>
  68  *    // Example: code fragment
  69  *    public class Customer {
  70  *        @XmlAttribute
  71  *        @XmlID
  72  *        public String getCustomerID();
  73  *        public void setCustomerID(String id);
  74  *        .... other properties not shown
  75  *    }
  76  *
  77  *    &lt;!-- Example: XML Schema fragment -->
  78  *    &lt;xs:complexType name="Customer">
  79  *      &lt;xs:complexContent>
  80  *        &lt;xs:sequence>
  81  *          ....
  82  *        &lt;/xs:sequence>
  83  *        &lt;xs:attribute name="customerID" type="xs:ID"/>
  84  *      &lt;/xs:complexContent>
  85  *    &lt;/xs:complexType>
  86  * </pre>
  87  *
  88  * @author Sekhar Vajjhala, Sun Microsystems, Inc.
  89  * @see XmlIDREF
  90  * @since JAXB2.0
  91  */
  92 
  93 @Retention(RUNTIME) @Target({FIELD, METHOD})
  94 public @interface XmlID { }