01: /*
02: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
03: *
04: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
05: *
06: * The contents of this file are subject to the terms of either the GNU
07: * General Public License Version 2 only ("GPL") or the Common Development
08: * and Distribution License("CDDL") (collectively, the "License"). You
09: * may not use this file except in compliance with the License. You can obtain
10: * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
11: * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
12: * language governing permissions and limitations under the License.
13: *
14: * When distributing the software, include this License Header Notice in each
15: * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
16: * Sun designates this particular file as subject to the "Classpath" exception
17: * as provided by Sun in the GPL Version 2 section of the License file that
18: * accompanied this code. If applicable, add the following below the License
19: * Header, with the fields enclosed by brackets [] replaced by your own
20: * identifying information: "Portions Copyrighted [year]
21: * [name of copyright owner]"
22: *
23: * Contributor(s):
24: *
25: * If you wish your version of this file to be governed by only the CDDL or
26: * only the GPL Version 2, indicate your decision by adding "[Contributor]
27: * elects to include this software in this distribution under the [CDDL or GPL
28: * Version 2] license." If you don't indicate a single choice of license, a
29: * recipient has the option to distribute your version of this file under
30: * either the CDDL, the GPL Version 2 or to extend the choice of license to
31: * its licensees as provided above. However, if you add GPL Version 2 code
32: * and therefore, elected the GPL Version 2 license, then the option applies
33: * only if the new code is made subject to such option by the copyright
34: * holder.
35: */
36: package javax.persistence;
37:
38: import java.lang.annotation.Target;
39: import java.lang.annotation.Retention;
40: import static java.lang.annotation.ElementType.TYPE;
41: import static java.lang.annotation.RetentionPolicy.RUNTIME;
42:
43: /**
44: * Is used to specify the value of the discriminator column for
45: * entities of the given type. The <code>DiscriminatorValue</code>
46: * annotation can only be specified on a concrete entity
47: * class. If the <code>DiscriminatorValue</code> annotation is not
48: * specified and a discriminator column is used, a provider-specific
49: * function will be used to generate a value representing the
50: * entity type. If the {@link DiscriminatorType} is {@link
51: * DiscriminatorType#STRING STRING}, the discriminator value
52: * default is the entity name.
53: *
54: * <p> The inheritance strategy and the discriminator column
55: * are only specified in the root of an entity class hierarchy
56: * or subhierarchy in which a different inheritance strategy is
57: * applied. The discriminator value, if not defaulted, should be
58: * specified for each entity class in the hierarchy.
59: *
60: * <pre>
61: *
62: * Example:
63: *
64: * @Entity
65: * @Table(name="CUST")
66: * @Inheritance(strategy=SINGLE_TABLE)
67: * @DiscriminatorColumn(name="DISC", discriminatorType=STRING,length=20)
68: * @DiscriminatorValue("CUSTOMER")
69: * public class Customer { ... }
70: *
71: * @Entity
72: * @DiscriminatorValue("VCUSTOMER")
73: * public class ValuedCustomer extends Customer { ... }
74: * </pre>
75: *
76: * @since Java Persistence 1.0
77: */
78: @Target({TYPE})
79: @Retention(RUNTIME)
80: public @interface DiscriminatorValue {
81:
82: /**
83: * (Optional) The value that indicates that the
84: * row is an entity of the annotated entity type.
85: *
86: * <p> If the <code>DiscriminatorValue</code> annotation is not
87: * specified and a discriminator column is used, a provider-specific
88: * function will be used to generate a value representing the
89: * entity type. If the DiscriminatorType is {@link
90: * DiscriminatorType#STRING STRING}, the discriminator value
91: * default is the entity name.
92: */
93: String value();
94: }
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