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Java > Open Source Codes > org > jaxen > expr > DefaultAndExpr


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultAndExpr.java,v 1.12 2005/05/16 10:46:43 elharo Exp $
3  * $Revision: 1.12 $
4  * $Date: 2005/05/16 10:46:43 $
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 1.12 2005/05/16 10:46:43 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
70 {
71     DefaultAndExpr(Expr lhs,
72                           Expr rhs)
73     {
74         super( lhs,
75                rhs );
76     }
77
78     public String JavaDoc getOperator()
79     {
80         return "and";
81     }
82
83     public String JavaDoc toString()
84     {
85         return "[(DefaultAndExpr): " + getLHS() + ", " + getRHS() + "]";
86     }
87
88     public Object JavaDoc evaluate(Context context) throws JaxenException
89     {
90         Navigator nav = context.getNavigator();
91         Boolean JavaDoc lhsValue = BooleanFunction.evaluate( getLHS().evaluate( context ), nav );
92
93         if ( !lhsValue.booleanValue() )
94         {
95             return Boolean.FALSE;
96         }
97
98         // Short circuits are required in XPath. "The right operand is not
99 // evaluated if the left operand evaluates to false."
100 Boolean JavaDoc rhsValue = BooleanFunction.evaluate( getRHS().evaluate( context ), nav );
101
102         if ( !rhsValue.booleanValue() )
103         {
104             return Boolean.FALSE;
105         }
106
107         return Boolean.TRUE;
108     }
109     
110     public void accept(Visitor visitor)
111     {
112         visitor.visit(this);
113     }
114     
115 }
116
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