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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package javax.jdo.annotations;
18  
19  import java.lang.annotation.ElementType;
20  import java.lang.annotation.Retention;
21  import java.lang.annotation.RetentionPolicy;
22  import java.lang.annotation.Target;
23  
24  /**
25   * Annotation for a database index. Used for database schema
26   * generation to create indexes.
27   * Corresponds to the xml element "index".
28   *
29   * @version 2.1
30   * @since 2.1
31   */
32  @Target({ElementType.TYPE, ElementType.FIELD, ElementType.METHOD}) 
33  @Retention(RetentionPolicy.RUNTIME)
34  public @interface Index
35  {
36      /** Name of the index
37       * @return the name of the index
38       */
39      String name() default "";
40  
41      /** Table for the index. This is needed iff annotating a type where
42       * the index is not defined on the primary table for the type.
43       * @return the table on which the index is defined
44       */
45      String table() default "";
46  
47      /** Whether this index is unique
48       * @return whether this index is unique
49       */
50      String unique() default "";
51  
52      /** Member (field and property) names that compose this index.
53       * @return member names that compose this index
54       */
55      String[] members() default {};
56  
57      /** Columns that compose this index.
58       * @return columns that compose this index
59       */
60      Column[] columns() default {};
61  }