1   /**
2    * Distribution License:
3    * JSword is free software; you can redistribute it and/or modify it under
4    * the terms of the GNU Lesser General Public License, version 2.1 as published by
5    * the Free Software Foundation. This program is distributed in the hope
6    * that it will be useful, but WITHOUT ANY WARRANTY; without even the
7    * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
8    * See the GNU Lesser General Public License for more details.
9    *
10   * The License is available on the internet at:
11   *       http://www.gnu.org/copyleft/lgpl.html
12   * or by writing to:
13   *      Free Software Foundation, Inc.
14   *      59 Temple Place - Suite 330
15   *      Boston, MA 02111-1307, USA
16   *
17   * Copyright: 2005
18   *     The copyright to this program is held by it's authors.
19   *
20   * ID: $Id:OrQuery.java 984 2006-01-23 14:18:33 -0500 (Mon, 23 Jan 2006) dmsmith $
21   */
22  package org.crosswire.jsword.index.query;
23  
24  import org.crosswire.jsword.book.BookException;
25  import org.crosswire.jsword.index.Index;
26  import org.crosswire.jsword.passage.Key;
27  import org.crosswire.jsword.passage.PassageTally;
28  
29  /**
30   * An OR query specifies that a result is the union of the left and the right
31   * query results.
32   * 
33   * @see gnu.lgpl.License for license details.<br>
34   *      The copyright to this program is held by it's authors.
35   * @author DM Smith [ dmsmith555 at yahoo dot com]
36   */
37  public class OrQuery extends AbstractBinaryQuery {
38  
39      /**
40       *
41       */
42      public OrQuery(Query theLeftQuery, Query theRightQuery) {
43          super(theLeftQuery, theRightQuery);
44      }
45  
46      /*
47       * (non-Javadoc)
48       * 
49       * @see
50       * org.crosswire.jsword.index.search.parse.Query#find(org.crosswire.jsword
51       * .index.search.Index)
52       */
53      public Key find(Index index) throws BookException {
54          Key left = getLeftQuery().find(index);
55          Key right = getRightQuery().find(index);
56  
57          if (left.isEmpty()) {
58              return right;
59          }
60  
61          if (right.isEmpty()) {
62              return left;
63          }
64  
65          // If ranking was requested then prioritize it.
66          if (right instanceof PassageTally) {
67              right.addAll(left);
68              return right;
69          }
70  
71          left.addAll(right);
72  
73          return left;
74      }
75  }
76