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Java > Open Source Codes > net > sf > jga > fn > arithmetic > BitwiseOr


1 // ============================================================================
2 // $Id: BitwiseOr.java,v 1.8 2006/08/07 04:02:50 davidahall Exp $
3 // Copyright (c) 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.arithmetic;
34
35 import java.text.MessageFormat JavaDoc;
36 import net.sf.jga.fn.BinaryFunctor;
37 import net.sf.jga.fn.EvaluationException;
38
39 /**
40  * Binary Functor that returns the bitwise or of its two arguments
41  * <p>
42  * Copyright &copy; 2005 David A. Hall
43  *
44  * @author <a HREF="mailto:davidahall@users.sourceforge.net">David A. Hall</a>
45  **/
46
47 public class BitwiseOr<T extends Number JavaDoc> extends BinaryFunctor<T,T,T> {
48
49     static final long serialVersionUID = -213586968622137607L;
50     
51     // Utility class that performs the math as appropriate for the class given at construction
52 transient private IntegerArithmetic<T> _math;
53      
54     // The type of operands this instance supports
55 private Class JavaDoc<T> _type;
56      
57     /**
58      * Builds BitwiseOr functor for the given class. The class argument must
59      * be the same as the generic class argument (when generics are in use)
60      * or else a ClassCastException will be thrown when the functor is used.
61      *
62      * @throws IllegalArgumentException if the given class has no Arithmetic
63      * implementation registered with the ArithmeticFactory
64      */
65     public BitwiseOr(Class JavaDoc<T> c) {
66         _type = c;
67         getMath();
68     }
69     
70     /**
71      * Returns the type of operands this instance supports
72      */
73     public Class JavaDoc<T> getType() {
74         return _type;
75     }
76     
77     // BinaryFunctor interface
78
79     /**
80      * Given arguments <b>x</b> and <b>y</b>, x | y
81      * @return x | y
82      */
83     public T fn(T x, T y) {
84         try {
85             return getMath().or(x, y);
86         }
87         catch (ClassCastException JavaDoc ex) {
88             String JavaDoc msg = "ClassCastException: Cannot compute {0}[{1}] | {2}[{3}]";
89             String JavaDoc err = MessageFormat.format(msg, new Object JavaDoc[]{ x.getClass(), x, y.getClass(), y});
90             throw new EvaluationException(err, ex);
91         }
92     }
93
94     /**
95      * Calls the Visitor's <code>visit(BitwiseOr)</code> method, if it
96      * implements the nested Visitor interface.
97      */
98     public void accept(net.sf.jga.fn.Visitor v) {
99         if (v instanceof BitwiseOr.Visitor)
100             ((BitwiseOr.Visitor)v).visit(this);
101         else
102             v.visit(this);
103     }
104
105     /**
106      */
107     private IntegerArithmetic<T> getMath() {
108         if (_math == null) {
109             _math = ArithmeticFactory.getIntegralArithmetic(_type);
110             if (_math == null) {
111                 String JavaDoc msg = "No implementation of IntegerArithmetic registered for {0}";
112                 throw new IllegalArgumentException JavaDoc(MessageFormat.format(msg, new Object JavaDoc[]{_type}));
113             }
114         }
115
116         return _math;
117     }
118     
119     // Object overrides
120
121     public String JavaDoc toString() {
122         return "BitwiseOr";
123     }
124     
125     // AcyclicVisitor
126
127     /**
128      * Interface for classes that may interpret a <b>BitwiseOr</b>
129      * functor.
130      */
131     public interface Visitor extends net.sf.jga.fn.Visitor {
132         public void visit(BitwiseOr host);
133     }
134
135 }
136
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