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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.core.cursor;
21  
22  
23  /**
24   * A monitor used by Cursors to detect conditions when they should stop 
25   * performing some work during advance operations such as next(), previous(),
26   * first() etc, and release resources.
27   *
28   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
29   * @version $Rev$, $Date$
30   */
31  public interface ClosureMonitor
32  {
33      /**
34       * Sets monitor state to closed, and sets the cause to a 
35       * CursorClosedException without an error message string.
36       */
37      void close();
38  
39      
40      /**
41       * Sets monitor state to closed, and sets the cause to a 
42       * CursorClosedException with a specific error message string.
43       * 
44       * @param cause error message string
45       */
46      void close( String cause );
47      
48      
49      /**
50       * Sets monitor state to closed, and sets the cause to a specific 
51       * Exception.
52       * 
53       * @param cause the exception to associate with the closure
54       */
55      void close( Exception cause );
56      
57      
58      /**
59       * Gets whether the state of this ClosureMonitor is set to closed.
60       *
61       * @return true if state is closed, false if open
62       */
63      boolean isClosed();
64      
65      
66      /**
67       * Checks if state of this ClosureMonitor is set to closed and if so, 
68       * throws the causing Exception.
69       *
70       * @throws Exception the cause of the closure
71       */
72      void checkNotClosed() throws Exception;
73      
74      
75      /**
76       * Gets the cause of the closure.
77       *
78       * @return the causing Exception
79       */
80      Exception getCause();
81  }