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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  package org.apache.directory.server.xdbm;
21  
22  
23  import org.apache.directory.server.core.cursor.Cursor;
24  
25  
26  /**
27   * A Cursor introducing new advance methods designed to reduce some
28   * inefficiencies encountered when scanning over Tuples.
29   *
30   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
31   * @version $Rev$
32   */
33  public interface IndexCursor<V,E> extends Cursor<IndexEntry<V,E>>
34  {
35      /**
36       * An alternative to calling before(IndexEntry) which often may require
37       * wrapping an id and value in a newly created IndexEntry object that may
38       * be an unnecessary object creation.  Some implementations may not
39       * support this operation and may throw an UnsupportedOperationEception.
40       *
41       * @param id the Long id for the entry
42       * @param indexValue the value to advance just before
43       * @throws Exception if there are faults peforming this operation
44       */
45      void beforeValue( Long id, V indexValue ) throws Exception;
46  
47  
48      /**
49       * An alternative to calling after(IndexEntry) which often may require
50       * wrapping an id and value in a newly created IndexEntry object that may
51       * be an unnecessary object creation.  Some implementations may not
52       * support this operation and may throw an UnsupportedOperationEception.
53       *
54       * @param id the Long id for the entry
55       * @param indexValue the value to advance just after the last value
56       * @throws Exception if there are faults peforming this operation
57       */
58      void afterValue( Long id, V indexValue ) throws Exception;
59  }