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1   /**
2    * JDBM LICENSE v1.00
3    *
4    * Redistribution and use of this software and associated documentation
5    * ("Software"), with or without modification, are permitted provided
6    * that the following conditions are met:
7    *
8    * 1. Redistributions of source code must retain copyright
9    *    statements and notices.  Redistributions must also contain a
10   *    copy of this document.
11   *
12   * 2. Redistributions in binary form must reproduce the
13   *    above copyright notice, this list of conditions and the
14   *    following disclaimer in the documentation and/or other
15   *    materials provided with the distribution.
16   *
17   * 3. The name "JDBM" must not be used to endorse or promote
18   *    products derived from this Software without prior written
19   *    permission of Cees de Groot.  For written permission,
20   *    please contact cg@cdegroot.com.
21   *
22   * 4. Products derived from this Software may not be called "JDBM"
23   *    nor may "JDBM" appear in their names without prior written
24   *    permission of Cees de Groot.
25   *
26   * 5. Due credit should be given to the JDBM Project
27   *    (http://jdbm.sourceforge.net/).
28   *
29   * THIS SOFTWARE IS PROVIDED BY THE JDBM PROJECT AND CONTRIBUTORS
30   * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
31   * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
32   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
33   * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
34   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
35   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
36   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
38   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
39   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
40   * OF THE POSSIBILITY OF SUCH DAMAGE.
41   *
42   * Copyright 2001 (C) Alex Boisvert. All Rights Reserved.
43   * Contributions are Copyright (C) 2001 by their associated contributors.
44   *
45   */
46  
47  package jdbm.helper;
48  
49  import java.io.IOException;
50  
51  /**
52   * Browser to traverse a collection of tuples.  The browser allows for
53   * forward and reverse order traversal.
54   *
55   * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
56   * @version $Id: TupleBrowser.java,v 1.2 2001/05/19 14:02:00 boisvert Exp $
57   */
58  public abstract class TupleBrowser {
59  
60      /**
61       * Get the next tuple.
62       *
63       * @param tuple Tuple into which values are copied.
64       * @return True if values have been copied in tuple, or false if there is
65       *         no next tuple.
66       */
67      public abstract boolean getNext( Tuple tuple )
68          throws IOException;
69  
70  
71      /**
72       * Get the previous tuple.
73       *
74       * @param tuple Tuple into which values are copied.
75       * @return True if values have been copied in tuple, or false if there is
76       *         no previous tuple.
77       */
78      public abstract boolean getPrevious( Tuple tuple )
79          throws IOException;
80  
81  }