DiscriminatorValue


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.TYPE  ;
28  import static java.lang.annotation.RetentionPolicy.RUNTIME  ;
29  
30  /**
31   * Is used to specify the value of the discriminator column for 
32   * entities of the given type. The <code>DiscriminatorValue</code> 
33   * annotation can only be specified on a concrete entity 
34   * class. If the <code>DiscriminatorValue</code> annotation is not 
35   * specified and a discriminator column is used, a provider-specific 
36   * function will be used to generate a value representing the 
37   * entity type.  If the {@link DiscriminatorType} is {@link 
38   * DiscriminatorType#STRING STRING}, the discriminator value 
39   * default is the entity name. 
40   *
41   * <p> The inheritance strategy and the discriminator column 
42   * are only specified in the root of an entity class hierarchy 
43   * or subhierarchy in which a different inheritance strategy is 
44   * applied. The discriminator value, if not defaulted, should be 
45   * specified for each entity class in the hierarchy.
46   *
47   * <pre>
48   *
49   *    Example:
50   *
51   *    &#064;Entity
52   *    &#064;Table(name="CUST")
53   *    &#064;Inheritance(strategy=SINGLE_TABLE)
54   *    &#064;DiscriminatorColumn(name="DISC", discriminatorType=STRING,length=20)
55   *    &#064;DiscriminatorValue("CUSTOMER")
56   *    public class Customer { ... }
57   *
58   *    &#064;Entity
59   *    &#064;DiscriminatorValue("VCUSTOMER")
60   *    public class ValuedCustomer extends Customer { ... }
61   * </pre>
62   *
63   * @since Java Persistence 1.0
64   */
65  @Target  ({TYPE}) 
66  @Retention  (RUNTIME)
67  
68  public @interface DiscriminatorValue {
69  
70      /**
71       * (Optional) The value that indicates that the
72       * row is an entity of the annotated entity type.
73       *
74       * <p> If the <code>DiscriminatorValue</code> annotation is not 
75       * specified and a discriminator column is used, a provider-specific 
76       * function will be used to generate a value representing the 
77       * entity type.  If the DiscriminatorType is {@link 
78       * DiscriminatorType#STRING STRING}, the discriminator value 
79       * default is the entity name. 
80       */
81      String   value();
82  }
83
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags