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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultAndExpr.java,v 1.9 2005/03/21 22:39:16 elharo Exp $
3    * $Revision: 1.9 $
4    * $Date: 2005/03/21 22:39:16 $
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: DefaultAndExpr.java,v 1.9 2005/03/21 22:39:16 elharo Exp $
60   */
61  
62  package org.jaxen.expr;
63  
64  import org.jaxen.Context;
65  import org.jaxen.JaxenException;
66  import org.jaxen.Navigator;
67  import org.jaxen.function.BooleanFunction;
68  
69  class DefaultAndExpr extends DefaultLogicalExpr implements LogicalExpr
70  {
71      public DefaultAndExpr(Expr lhs,
72                            Expr rhs)
73      {
74          super( lhs,
75                 rhs );
76      }
77  
78      public String getOperator()
79      {
80          return "and";
81      }
82  
83      public String toString()
84      {
85          return "[(DefaultAndExpr): " + getLHS() + ", " + getRHS() + "]";
86      }
87  
88      public Object evaluate(Context context) throws JaxenException
89      {
90          Navigator nav = context.getNavigator();
91          Boolean lhsValue = BooleanFunction.evaluate( getLHS().evaluate( context ), nav );
92  
93          if ( lhsValue == Boolean.FALSE )
94          {
95              return Boolean.FALSE;
96          }
97  
98          Boolean rhsValue = BooleanFunction.evaluate( getRHS().evaluate( context ), nav );
99  
100         if ( rhsValue == Boolean.FALSE )
101         {
102             return Boolean.FALSE;
103         }
104 
105         return Boolean.TRUE;
106     }
107     public void accept(Visitor visitor)
108     {
109         visitor.visit(this);
110     }
111 }