View Javadoc

1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultTruthExpr.java,v 1.6 2003/06/29 18:05:40 ssanders Exp $
3    * $Revision: 1.6 $
4    * $Date: 2003/06/29 18:05:40 $
5    *
6    * ====================================================================
7    *
8    * Copyright (C) 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
13   * are met:
14   * 
15   * 1. Redistributions of source code must retain the above copyright
16   *    notice, this list of conditions, and the following disclaimer.
17   *
18   * 2. Redistributions in binary form must reproduce the above copyright
19   *    notice, this list of conditions, and the disclaimer that follows 
20   *    these conditions in the documentation and/or other materials 
21   *    provided with the distribution.
22   *
23   * 3. The name "Jaxen" must not be used to endorse or promote products
24   *    derived from this software without prior written permission.  For
25   *    written permission, please contact license@jaxen.org.
26   * 
27   * 4. Products derived from this software may not be called "Jaxen", nor
28   *    may "Jaxen" appear in their name, without prior written permission
29   *    from the Jaxen Project Management (pm@jaxen.org).
30   * 
31   * In addition, we request (but do not require) that you include in the 
32   * end-user documentation provided with the redistribution and/or in the 
33   * software itself an acknowledgement equivalent to the following:
34   *     "This product includes software developed by the
35   *      Jaxen Project (http://www.jaxen.org/)."
36   * Alternatively, the acknowledgment may be graphical using the logos 
37   * available at http://www.jaxen.org/
38   *
39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50   * SUCH DAMAGE.
51   *
52   * ====================================================================
53   * This software consists of voluntary contributions made by many 
54   * individuals on behalf of the Jaxen Project and was originally 
55   * created by bob mcwhirter <bob@werken.com> and 
56   * James Strachan <jstrachan@apache.org>.  For more information on the 
57   * Jaxen Project, please see <http://www.jaxen.org/>.
58   * 
59   * $Id: DefaultTruthExpr.java,v 1.6 2003/06/29 18:05:40 ssanders Exp $
60   */
61  
62  
63  
64  package org.jaxen.expr;
65  
66  import java.util.List;
67  
68  abstract class DefaultTruthExpr extends DefaultBinaryExpr 
69  {
70      public DefaultTruthExpr(Expr lhs,
71                              Expr rhs)
72      {
73          super( lhs,
74                 rhs );
75      }
76  
77      public String toString()
78      {
79          return "[(DefaultTruthExpr): " + getLHS() + ", " + getRHS() + "]";
80      }
81  
82      protected boolean bothAreSets(Object lhs,
83                                    Object rhs)
84      {
85          return ( lhs instanceof List
86                   &&
87                   rhs instanceof List );
88      }
89  
90      protected boolean eitherIsSet(Object lhs,
91                                    Object rhs)
92      {
93          return ( lhs instanceof List
94                   ||
95                   rhs instanceof List );
96      }
97  
98      protected boolean isSet(Object obj)
99      {
100         return ( obj instanceof List );
101     }
102     
103     protected boolean setIsEmpty( List set )
104       {
105       return (set == null || set.size() == 0);
106       }
107 
108     protected boolean eitherIsBoolean(Object lhs,
109                                       Object rhs)
110     {
111         return ( lhs instanceof Boolean
112                  ||
113                  rhs instanceof Boolean );
114     }
115 
116     protected boolean bothAreBoolean(Object lhs,
117                                      Object rhs)
118     {
119         return ( lhs instanceof Boolean
120                  &&
121                  rhs instanceof Boolean );
122     }
123 
124     protected boolean eitherIsNumber(Object lhs,
125                                      Object rhs)
126     {
127         return ( lhs instanceof Number
128                  ||
129                  rhs instanceof Number );
130     }
131 
132     protected boolean isNumber(Object obj)
133     {
134         return ( obj instanceof Number );
135     }
136 
137     protected boolean isString(Object obj)
138     {
139         return ( obj instanceof String );
140     }
141 
142     protected boolean isBoolean(Object obj)
143     {
144         return ( obj instanceof Boolean );
145     }
146 }
147