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Java > Open Source Codes > net > sf > jga > fn > logical > LogicalOr


1 // ============================================================================
2 // $Id: LogicalOr.java,v 1.12 2006/01/08 00:52:25 davidahall Exp $
3 // Copyright (c) 2002-2005 David A. Hall
4 // ============================================================================
5 // The contents of this file are subject to the Common Development and
6 // Distribution License (CDDL), Version 1.0 (the License); you may not use this
7 // file except in compliance with the License. You should have received a copy
8 // of the the License along with this file: if not, a copy of the License is
9 // available from Sun Microsystems, Inc.
10 //
11 // http://www.sun.com/cddl/cddl.html
12 //
13 // From time to time, the license steward (initially Sun Microsystems, Inc.) may
14 // publish revised and/or new versions of the License. You may not use,
15 // distribute, or otherwise make this file available under subsequent versions
16 // of the License.
17 //
18 // Alternatively, the contents of this file may be used under the terms of the
19 // GNU Lesser General Public License Version 2.1 or later (the "LGPL"), in which
20 // case the provisions of the LGPL are applicable instead of those above. If you
21 // wish to allow use of your version of this file only under the terms of the
22 // LGPL, and not to allow others to use your version of this file under the
23 // terms of the CDDL, indicate your decision by deleting the provisions above
24 // and replace them with the notice and other provisions required by the LGPL.
25 // If you do not delete the provisions above, a recipient may use your version
26 // of this file under the terms of either the CDDL or the LGPL.
27 //
28 // This library is distributed in the hope that it will be useful,
29 // but WITHOUT ANY WARRANTY; without even the implied warranty of
30 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
31 // ============================================================================
32
33 package net.sf.jga.fn.logical;
34
35 import net.sf.jga.fn.BinaryPredicate;
36
37 /**
38  * Binary Predicate that returns true when either of Boolean arguments <b>x</b>
39  * and <b>y</b> are true.
40  * <p>
41  * Note that this functor does <i>not</i> short circuit the evaluation
42  * of the second argument. The reason for this is that, by itself,
43  * this functor accepts only boolean arguments. When it is used in
44  * conjunction with the adaptor functors to implement compound
45  * functors, the adaptor cannot know that the functor it is adapting
46  * may not need to use both arguments, so the adaptor will fully
47  * evaluate both arguments before passing them to the And functor.
48  * This would give the illusion that the short circuit logic is
49  * broken, when it is in fact unimplementable using the standard
50  * functor mechanism.
51  * <p>
52  * Copyright &copy; 2002-2005 David A. Hall
53  *
54  * @author <a HREF="mailto:davidahall@users.sourceforge.net">David A. Hall</a>
55  **/
56
57 public class LogicalOr extends BinaryPredicate<Boolean JavaDoc, Boolean JavaDoc> {
58
59     static final long serialVersionUID = -5329467559457020210L;
60     
61     // BinaryPredicate interface
62
63     /**
64      * Given Boolean arguments <b>x</b> and <b>y</b>, returns true when either
65      * x and y are true, otherwise false.
66      *
67      * @return x | y
68      */
69     public Boolean JavaDoc fn(Boolean JavaDoc x, Boolean JavaDoc y) {
70         return x | y;
71     }
72
73     /**
74      * Calls the Visitor's <code>visit(LogicalOr)</code> method, if it
75      * implements the nested Visitor interface.
76      */
77     public void accept(net.sf.jga.fn.Visitor v) {
78         if (v instanceof LogicalOr.Visitor)
79             ((LogicalOr.Visitor)v).visit(this);
80         else
81             v.visit(this);
82     }
83     
84     // Object overrides
85
86     public String JavaDoc toString() {
87         return "LogicalOr";
88     }
89     
90     // AcyclicVisitor
91
92     /**
93      * Interface for classes that may interpret a <b>LogicalOr</b>
94      * predicate.
95      */
96     public interface Visitor extends net.sf.jga.fn.Visitor {
97         public void visit(LogicalOr bp);
98     }
99 }
100
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