ohair@286: /*
ohair@286:  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
ohair@286:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ohair@286:  *
ohair@286:  * This code is free software; you can redistribute it and/or modify it
ohair@286:  * under the terms of the GNU General Public License version 2 only, as
ohair@286:  * published by the Free Software Foundation.  Oracle designates this
ohair@286:  * particular file as subject to the "Classpath" exception as provided
ohair@286:  * by Oracle in the LICENSE file that accompanied this code.
ohair@286:  *
ohair@286:  * This code is distributed in the hope that it will be useful, but WITHOUT
ohair@286:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ohair@286:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ohair@286:  * version 2 for more details (a copy is included in the LICENSE file that
ohair@286:  * accompanied this code).
ohair@286:  *
ohair@286:  * You should have received a copy of the GNU General Public License version
ohair@286:  * 2 along with this work; if not, write to the Free Software Foundation,
ohair@286:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ohair@286:  *
ohair@286:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@286:  * or visit www.oracle.com if you need additional information or have any
ohair@286:  * questions.
ohair@286:  */
ohair@286: 
ohair@286: package javax.xml.bind.annotation;
ohair@286: 
ohair@286: import java.lang.annotation.Target;
ohair@286: import java.lang.annotation.Retention;
ohair@286: import static java.lang.annotation.ElementType.*;
ohair@286: import static java.lang.annotation.RetentionPolicy.*;
ohair@286: 
ohair@286: /**
ohair@286:  * <p>
ohair@286:  * Maps a JavaBean property to XML IDREF.
ohair@286:  *
ohair@286:  * <p>
ohair@286:  * To preserve referential integrity of an object graph across XML
ohair@286:  * serialization followed by a XML deserialization, requires an object
ohair@286:  * reference to be marshalled by reference or containment
ohair@286:  * appropriately. Annotations <tt>&#64;XmlID</tt> and <tt>&#64;XmlIDREF</tt>
ohair@286:  * together allow a customized mapping of a JavaBean property's
ohair@286:  * type by containment or reference.
ohair@286:  *
ohair@286:  * <p><b>Usage</b> </p>
ohair@286:  * The <tt>&#64;XmlIDREF</tt> annotation can be used with the following
ohair@286:  * program elements:
ohair@286:  * <ul>
ohair@286:  *   <li> a JavaBean property </li>
ohair@286:  *   <li> non static, non transient field </li>
ohair@286:  * </ul>
ohair@286:  *
ohair@286:  * <p>See "Package Specification" in javax.xml.bind.package javadoc for
ohair@286:  * additional common information.</p>
ohair@286:  *
ohair@286:  * <p> The usage is subject to the following constraints:
ohair@286:  * <ul>
ohair@286:  *
ohair@286:  *   <li> If the type of the field or property is a collection type,
ohair@286:  *        then the collection item type must contain a property or
ohair@286:  *        field annotated with <tt>&#64;XmlID</tt>.  </li>
ohair@286:  *   <li> If the field or property is single valued, then the type of
ohair@286:  *        the property or field must contain a property or field
ohair@286:  *        annotated with <tt>&#64;XmlID</tt>.
ohair@286:  *        <p>Note: If the collection item type or the type of the
ohair@286:  *        property (for non collection type) is java.lang.Object, then
ohair@286:  *        the instance must contain a property/field annotated with
ohair@286:  *        <tt>&#64;XmlID</tt> attribute.
ohair@286:  *        </li>
ohair@286:  *   <li> This annotation can be used with the following annotations:
ohair@286:  *        {@link XmlElement}, {@link XmlAttribute}, {@link XmlList},
ohair@286:  *        and {@link XmlElements}.</li>
ohair@286:  *
ohair@286:  * </ul>
ohair@286:  * <p><b>Example:</b> Map a JavaBean property to <tt>xs:IDREF</tt>
ohair@286:  *   (i.e. by reference rather than by containment)</p>
ohair@286:  * <pre>
ohair@286:  *
ohair@286:  *   //EXAMPLE: Code fragment
ohair@286:  *   public class Shipping {
ohair@286:  *       &#64;XmlIDREF public Customer getCustomer();
ohair@286:  *       public void setCustomer(Customer customer);
ohair@286:  *       ....
ohair@286:  *    }
ohair@286:  *
ohair@286:  *   &lt;!-- Example: XML Schema fragment -->
ohair@286:  *   &lt;xs:complexType name="Shipping">
ohair@286:  *     &lt;xs:complexContent>
ohair@286:  *       &lt;xs:sequence>
ohair@286:  *         &lt;xs:element name="customer" type="xs:IDREF"/>
ohair@286:  *         ....
ohair@286:  *       &lt;/xs:sequence>
ohair@286:  *     &lt;/xs:complexContent>
ohair@286:  *   &lt;/xs:complexType>
ohair@286:  *
ohair@286:  * </pre>
ohair@286:  *
ohair@286:  *
ohair@286:  * <p><b>Example 2: </b> The following is a complete example of
ohair@286:  * containment versus reference.
ohair@286:  *
ohair@286:  * <pre>
ohair@286:  *    // By default, Customer maps to complex type <tt>xs:Customer</tt>
ohair@286:  *    public class Customer {
ohair@286:  *
ohair@286:  *        // map JavaBean property type to <tt>xs:ID</tt>
ohair@286:  *        &#64;XmlID public String getCustomerID();
ohair@286:  *        public void setCustomerID(String id);
ohair@286:  *
ohair@286:  *        // .... other properties not shown
ohair@286:  *    }
ohair@286:  *
ohair@286:  *
ohair@286:  *   // By default, Invoice maps to a complex type <tt>xs:Invoice</tt>
ohair@286:  *   public class Invoice {
ohair@286:  *
ohair@286:  *       // map by reference
ohair@286:  *       &#64;XmlIDREF public Customer getCustomer();
ohair@286:  *       public void setCustomer(Customer customer);
ohair@286:  *
ohair@286:  *      // .... other properties not shown here
ohair@286:  *   }
ohair@286:  *
ohair@286:  *   // By default, Shipping maps to complex type <tt>xs:Shipping</tt>
ohair@286:  *   public class Shipping {
ohair@286:  *
ohair@286:  *       // map by reference
ohair@286:  *       &#64;XmlIDREF public Customer getCustomer();
ohair@286:  *       public void setCustomer(Customer customer);
ohair@286:  *   }
ohair@286:  *
ohair@286:  *   // at least one class must reference Customer by containment;
ohair@286:  *   // Customer instances won't be marshalled.
ohair@286:  *   &#64;XmlElement(name="CustomerData")
ohair@286:  *   public class CustomerData {
ohair@286:  *       // map reference to Customer by containment by default.
ohair@286:  *       public Customer getCustomer();
ohair@286:  *
ohair@286:  *       // maps reference to Shipping by containment by default.
ohair@286:  *       public Shipping getShipping();
ohair@286:  *
ohair@286:  *       // maps reference to Invoice by containment by default.
ohair@286:  *       public Invoice getInvoice();
ohair@286:  *   }
ohair@286:  *
ohair@286:  *   &lt;!-- XML Schema mapping for above code frament -->
ohair@286:  *
ohair@286:  *   &lt;xs:complexType name="Invoice">
ohair@286:  *     &lt;xs:complexContent>
ohair@286:  *       &lt;xs:sequence>
ohair@286:  *         &lt;xs:element name="customer" type="xs:IDREF"/>
ohair@286:  *         ....
ohair@286:  *       &lt;/xs:sequence>
ohair@286:  *     &lt;/xs:complexContent>
ohair@286:  *   &lt;/xs:complexType>
ohair@286:  *
ohair@286:  *   &lt;xs:complexType name="Shipping">
ohair@286:  *     &lt;xs:complexContent>
ohair@286:  *       &lt;xs:sequence>
ohair@286:  *         &lt;xs:element name="customer" type="xs:IDREF"/>
ohair@286:  *         ....
ohair@286:  *       &lt;/xs:sequence>
ohair@286:  *     &lt;/xs:complexContent>
ohair@286:  *   &lt;/xs:complexType>
ohair@286:  *
ohair@286:  *   &lt;xs:complexType name="Customer">
ohair@286:  *     &lt;xs:complexContent>
ohair@286:  *       &lt;xs:sequence>
ohair@286:  *         ....
ohair@286:  *       &lt;/xs:sequence>
ohair@286:  *       &lt;xs:attribute name="CustomerID" type="xs:ID"/>
ohair@286:  *     &lt;/xs:complexContent>
ohair@286:  *   &lt;/xs:complexType>
ohair@286:  *
ohair@286:  *   &lt;xs:complexType name="CustomerData">
ohair@286:  *     &lt;xs:complexContent>
ohair@286:  *       &lt;xs:sequence>
ohair@286:  *         &lt;xs:element name="customer" type="xs:Customer"/>
ohair@286:  *         &lt;xs:element name="shipping" type="xs:Shipping"/>
ohair@286:  *         &lt;xs:element name="invoice"  type="xs:Invoice"/>
ohair@286:  *       &lt;/xs:sequence>
ohair@286:  *     &lt;/xs:complexContent>
ohair@286:  *   &lt;/xs:complexType>
ohair@286:  *
ohair@286:  *   &lt;xs:element name"customerData" type="xs:CustomerData"/>
ohair@286:  *
ohair@286:  *   &lt;!-- Instance document conforming to the above XML Schema -->
ohair@286:  *    &lt;customerData>
ohair@286:  *       &lt;customer customerID="Alice">
ohair@286:  *           ....
ohair@286:  *       &lt;/customer>
ohair@286:  *
ohair@286:  *       &lt;shipping customer="Alice">
ohair@286:  *           ....
ohair@286:  *       &lt;/shipping>
ohair@286:  *
ohair@286:  *       &lt;invoice customer="Alice">
ohair@286:  *           ....
ohair@286:  *       &lt;/invoice>
ohair@286:  *   &lt;/customerData>
ohair@286:  *
ohair@286:  * </pre>
ohair@286:  *
ohair@286:  * <p><b>Example 3: </b> Mapping List to repeating element of type IDREF
ohair@286:  * <pre>
ohair@286:  *     // Code fragment
ohair@286:  *     public class Shipping {
ohair@286:  *         &#64;XmlIDREF
ohair@286:  *         &#64;XmlElement(name="Alice")
ohair@286:  *             public List customers;
ohair@286:  *     }
ohair@286:  *
ohair@286:  *     &lt;!-- XML schema fragment -->
ohair@286:  *     &lt;xs:complexType name="Shipping">
ohair@286:  *       &lt;xs:sequence>
ohair@286:  *         &lt;xs:choice minOccurs="0" maxOccurs="unbounded">
ohair@286:  *           &lt;xs:element name="Alice" type="xs:IDREF"/>
ohair@286:  *         &lt;/xs:choice>
ohair@286:  *       &lt;/xs:sequence>
ohair@286:  *     &lt;/xs:complexType>
ohair@286:  * </pre>
ohair@286:  *
ohair@286:  * <p><b>Example 4: </b> Mapping a List to a list of elements of type IDREF.
ohair@286:  * <pre>
ohair@286:  *     //Code fragment
ohair@286:  *     public class Shipping {
ohair@286:  *         &#64;XmlIDREF
ohair@286:  *         &#64;XmlElements(
ohair@286:  *             &#64;XmlElement(name="Alice", type="Customer.class")
ohair@286:  *              &#64;XmlElement(name="John", type="InternationalCustomer.class")
ohair@286:  *         public List customers;
ohair@286:  *     }
ohair@286:  *
ohair@286:  *     &lt;!-- XML Schema fragment -->
ohair@286:  *     &lt;xs:complexType name="Shipping">
ohair@286:  *       &lt;xs:sequence>
ohair@286:  *         &lt;xs:choice minOccurs="0" maxOccurs="unbounded">
ohair@286:  *           &lt;xs:element name="Alice" type="xs:IDREF"/>
ohair@286:  *           &lt;xs:element name="John" type="xs:IDREF"/>
ohair@286:  *         &lt;/xs:choice>
ohair@286:  *       &lt;/xs:sequence>
ohair@286:  *     &lt;/xs:complexType>
ohair@286:  * </pre>
ohair@286:  * @author Sekhar Vajjhala, Sun Microsystems, Inc.
ohair@286:  * @see XmlID
ohair@286:  * @since JAXB2.0
ohair@286:  */
ohair@286: 
ohair@286: @Retention(RUNTIME) @Target({FIELD, METHOD})
ohair@286: public @interface XmlIDREF {}