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.METHOD;
41: import static java.lang.annotation.ElementType.FIELD;
42: import static java.lang.annotation.RetentionPolicy.RUNTIME;
43:
44: /**
45: * This annotation specifies the version field or property of
46: * an entity class that serves as its optimistic lock value.
47: * The version is used to ensure integrity when performing the
48: * merge operation and for optimistic concurrency control.
49: *
50: * <p> Only a single <code>Version</code> property or field
51: * should be used per class; applications that use more than one
52: * <code>Version</code> property or field will not be portable.
53: *
54: * <p> The <code>Version</code> property should be mapped to
55: * the primary table for the entity class; applications that
56: * map the <code>Version</code> property to a table other than
57: * the primary table will not be portable.
58: *
59: * <p> The following types are supported for version properties:
60: * <code>int</code>, {@link Integer}, <code>short</code>,
61: * {@link Short}, <code>long</code>, {@link Long},
62: * {@link java.sql.Timestamp Timestamp}.
63: *
64: * <pre>
65: * Example:
66: *
67: * @Version
68: * @Column(name="OPTLOCK")
69: * protected int getVersionNum() { return versionNum; }
70: * </pre>
71: *
72: * @since Java Persistence 1.0
73: */
74: @Target({METHOD,FIELD})
75: @Retention(RUNTIME)
76: public @interface Version {
77: }
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