OrderBy


1   /*
2    * The contents of this file are subject to the terms 
3    * of the Common Development and Distribution License 
4    * (the License).  You may not use this file except in
5    * compliance with the License.
6    * 
7    * You can obtain a copy of the license at 
8    * https://glassfish.dev.java.net/public/CDDLv1.0.html or
9    * glassfish/bootstrap/legal/CDDLv1.0.txt.
10   * See the License for the specific language governing 
11   * permissions and limitations under the License.
12   * 
13   * When distributing Covered Code, include this CDDL 
14   * Header Notice in each file and include the License file 
15   * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
16   * If applicable, add the following below the CDDL Header, 
17   * with the fields enclosed by brackets [] replaced by
18   * you own identifying information: 
19   * "Portions Copyrighted [year] [name of copyright owner]"
20   * 
21   * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22   */
23  package javax.persistence;
24  
25  import java.lang.annotation.Target  ;
26  import java.lang.annotation.Retention  ;
27  import static java.lang.annotation.ElementType.METHOD  ;
28  import static java.lang.annotation.ElementType.FIELD  ;
29  import static java.lang.annotation.RetentionPolicy.RUNTIME  ;
30  
31  /**
32   * This annotation specifies the ordering of the elements of a 
33   * collection valued association at the point when the association 
34   * is retrieved.
35   * 
36   * <p> The syntax of the <code>value</code> ordering element is an 
37   * <code>orderby_list</code>, as follows:
38   * 
39   * <pre>
40   *    orderby_list::= orderby_item [,orderby_item]*
41   *    orderby_item::= property_or_field_name [ASC | DESC]
42   * </pre>
43   * 
44   * <p> If <code>ASC</code> or <code>DESC</code> is not specified, 
45   * <code>ASC</code> (ascending order) is assumed.
46   *
47   * <p> If the ordering element is not specified, ordering by 
48   * the primary key of the associated entity is assumed.
49   *
50   * <p> The property or field name must correspond to that of a 
51   * persistent property or field of the associated class. The 
52   * properties or fields used in the ordering must correspond to 
53   * columns for which comparison operators are supported.
54   *
55   * <pre>
56   *    Example:
57   *    
58   *    &#064;Entity public class Course {
59   *     ...
60   *     &#064;ManyToMany
61   *     &#064;OrderBy("lastname ASC")
62   *     public List<Student> getStudents() {...};
63   *     ...
64   *    }
65   *    
66   *    &#064;Entity public class Student {
67   *      ...
68   *      &#064;ManyToMany(mappedBy="students")
69   *      &#064;OrderBy // PK is assumed
70   *      public List<Course> getCourses() {...};
71   *      ...
72   *    }
73   * </pre>
74   *
75   * @since Java Persistence 1.0
76   */
77  @Target  ({METHOD, FIELD}) 
78  @Retention  (RUNTIME)
79  
80  public @interface OrderBy {
81  
82      /**
83      * An <code>orderby_list</code>, specified as follows:
84      *
85      * <pre>
86      *    orderby_list::= orderby_item [,orderby_item]*
87      *    orderby_item::= property_or_field_name [ASC | DESC]
88      * </pre>
89      *
90      * <p> If <code>ASC</code> or <code>DESC</code> is not specified,
91      * <code>ASC</code> (ascending order) is assumed.
92      *
93      * <p> If the ordering element is not specified, ordering by
94      * the primary key of the associated entity is assumed.
95      */
96      String   value() default "";
97  }
98
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