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


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultOrExpr.java,v 1.13 2005/05/16 10:48:12 elharo Exp $
3  * $Revision: 1.13 $
4  * $Date: 2005/05/16 10:48:12 $
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: DefaultOrExpr.java,v 1.13 2005/05/16 10:48:12 elharo Exp $
60  */
61
62
63
64 package org.jaxen.expr;
65
66 import org.jaxen.Context;
67 import org.jaxen.JaxenException;
68 import org.jaxen.Navigator;
69 import org.jaxen.function.BooleanFunction;
70
71 class DefaultOrExpr extends DefaultLogicalExpr
72 {
73     DefaultOrExpr(Expr lhs,
74                          Expr rhs)
75     {
76         super( lhs,
77                rhs );
78     }
79
80     public String JavaDoc getOperator()
81     {
82         return "or";
83     }
84
85     public String JavaDoc toString()
86     {
87         return "[(DefaultOrExpr): " + getLHS() + ", " + getRHS() + "]";
88     }
89
90     public Object JavaDoc evaluate(Context context) throws JaxenException
91     {
92         Navigator nav = context.getNavigator();
93         Boolean JavaDoc lhsValue = BooleanFunction.evaluate( getLHS().evaluate( context ), nav );
94
95         if ( lhsValue.booleanValue() )
96         {
97             return Boolean.TRUE;
98         }
99
100         // Short circuits are required in XPath. "The right operand is not
101 // evaluated if the left operand evaluates to true."
102 Boolean JavaDoc rhsValue = BooleanFunction.evaluate( getRHS().evaluate( context ), nav );
103
104         if ( rhsValue.booleanValue() )
105         {
106             return Boolean.TRUE;
107         }
108
109         return Boolean.FALSE;
110     }
111     
112     public void accept(Visitor visitor)
113     {
114         visitor.visit(this);
115     }
116     
117 }
118
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