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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  package org.apache.directory.server.core.cursor;
20  
21  
22  /**
23   * A Cursor's state: cursor states leverage the State Pattern to isolate state
24   * specific transition logic with certain operations.  Not every Cursor is
25   * that complex so the implementor should decide whether or not using the
26   * State Pattern is over kill on a per Cursor implementation basis.
27   *
28   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
29   * @version $Rev$, $Date$
30   */
31  public interface CursorState<E>
32  {
33      void before( E element ) throws Exception;
34  
35      void after( E element ) throws Exception;
36  
37      void beforeFirst() throws Exception;
38  
39      void afterLast() throws Exception;
40  
41      boolean first() throws Exception;
42  
43      boolean last() throws Exception;
44  
45      boolean previous() throws Exception;
46  
47      boolean next() throws Exception;
48  }