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1   /*
2    * $Header$
3    * $Revision: 1335 $
4    * $Date: 2008-11-30 06:20:38 -0800 (Sun, 30 Nov 2008) $
5    *
6    * ====================================================================
7    *
8    * Copyright 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions are
13   * met:
14   * 
15   *   * Redistributions of source code must retain the above copyright
16   *     notice, this list of conditions and the following disclaimer.
17   * 
18   *   * Redistributions in binary form must reproduce the above copyright
19   *     notice, this list of conditions and the following disclaimer in the
20   *     documentation and/or other materials provided with the distribution.
21   * 
22   *   * Neither the name of the Jaxen Project nor the names of its
23   *     contributors may be used to endorse or promote products derived 
24   *     from this software without specific prior written permission.
25   * 
26   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37   *
38   * ====================================================================
39   * This software consists of voluntary contributions made by many 
40   * individuals on behalf of the Jaxen Project and was originally 
41   * created by bob mcwhirter <bob@werken.com> and 
42   * James Strachan <jstrachan@apache.org>.  For more information on the 
43   * Jaxen Project, please see <http://www.jaxen.org/>.
44   * 
45   * $Id: DefaultTruthExpr.java 1335 2008-11-30 14:20:38Z elharo $
46   */
47  
48  
49  
50  package org.jaxen.expr;
51  
52  import java.util.List;
53  
54  abstract class DefaultTruthExpr extends DefaultBinaryExpr 
55  {
56      DefaultTruthExpr(Expr lhs,
57                              Expr rhs)
58      {
59          super( lhs,
60                 rhs );
61      }
62  
63      public String toString()
64      {
65          return "[(DefaultTruthExpr): " + getLHS() + ", " + getRHS() + "]";
66      }
67  
68      protected boolean bothAreSets(Object lhs,
69                                    Object rhs)
70      {
71          return ( lhs instanceof List
72                   &&
73                   rhs instanceof List );
74      }
75  
76      protected boolean eitherIsSet(Object lhs,
77                                    Object rhs)
78      {
79          return ( lhs instanceof List
80                   ||
81                   rhs instanceof List );
82      }
83  
84      protected boolean isSet(Object obj)
85      {
86          return ( obj instanceof List );
87      }
88      
89      protected boolean isBoolean(Object obj)
90      {
91          return ( obj instanceof Boolean );
92      }
93      
94      protected boolean setIsEmpty( List set )
95        {
96        return (set == null || set.size() == 0);
97        }
98  
99      protected boolean eitherIsBoolean(Object lhs,
100                                       Object rhs)
101     {
102         return ( lhs instanceof Boolean
103                  ||
104                  rhs instanceof Boolean );
105     }
106 
107     protected boolean bothAreBoolean(Object lhs,
108                                      Object rhs)
109     {
110         return ( lhs instanceof Boolean
111                  &&
112                  rhs instanceof Boolean );
113     }
114 
115     protected boolean eitherIsNumber(Object lhs,
116                                      Object rhs)
117     {
118         return ( lhs instanceof Number
119                  ||
120                  rhs instanceof Number );
121     } 
122 
123 }
124