KickJava   Java API By Example, From Geeks To Geeks.

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


1 // ============================================================================
2
// $Id: Divides.java,v 1.14 2006/04/26 03:15:55 davidahall Exp $
3
// Copyright (c) 2003-2005 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  * Returns the quotient of two numeric arguments.
41  * <p>
42  * Copyright &copy; 2003-2005 David A. Hall
43  *
44  * @author <a HREF="mailto:davidahall@users.sourceforge.net">David A. Hall</a>
45  */

46
47 public class Divides<T extends Number JavaDoc> extends BinaryFunctor<T,T,T> {
48     
49     static final long serialVersionUID = -1660400300772244025L;
50
51     // Utility class that performs the division as appropriate for the
52
// class given at construction
53
transient private Arithmetic<T> _math;
54
55     // The type of operands this instance supports
56
private Class JavaDoc<T> _type;
57      
58     /**
59      * Builds Divides functor for the given class. The class argument must
60      * be the same as the generic class argument (when generics are in use)
61      * or else a ClassCastException will be thrown when the functor is used.
62      *
63      * @throws IllegalArgumentException if the given class has no Arithmetic
64      * implementation registered with the ArithmeticFactory
65      */

66     public Divides(Class JavaDoc<T> c) {
67         _type = c;
68         getMath();
69     }
70     
71     /**
72      * Returns the type of operands this instance supports
73      */

74     public Class JavaDoc<T> getType() {
75         return _type;
76     }
77     
78     // Binary Functor interface
79

80     /**
81      * Given numeric arguments <b>x</b> and <b>y</b>, returns x / y
82      * @return the quotient of two numeric arguments
83      */

84     public T fn(T x, T y) {
85         try {
86             return getMath().divides(x, y);
87         }
88         catch (ClassCastException JavaDoc ex) {
89             String JavaDoc msg = "ClassCastException: Cannot divide {0}[{1}] by {2}[{3}]";
90             String JavaDoc err = MessageFormat.format(msg, new Object JavaDoc[]{ x.getClass(), x, y.getClass(), y});
91             throw new EvaluationException(err, ex);
92         }
93     }
94
95     /**
96      * Calls the Visitor's <code>visit(Divides)</code> method, if it implements
97      * the nested Visitor interface.
98      */

99     public void accept(net.sf.jga.fn.Visitor v) {
100         if (v instanceof Divides.Visitor)
101             ((Divides.Visitor)v).visit(this);
102         else
103             v.visit(this);
104     }
105     
106     /**
107      */

108     private Arithmetic<T> getMath() {
109         if (_math == null) {
110             _math = ArithmeticFactory.getArithmetic(_type);
111             if (_math == null) {
112                 String JavaDoc msg = "No implementation of Arithmetic registered for {0}";
113                 throw new IllegalArgumentException JavaDoc(MessageFormat.format(msg, new Object JavaDoc[]{_type}));
114             }
115         }
116
117         return _math;
118     }
119     
120     // Object overrides
121

122     public String JavaDoc toString() {
123         return "Divides";
124     }
125     
126     // AcyclicVisitor
127

128     /**
129      * Interface for classes that may interpret a <b>Divides</b> functor.
130      */

131     public interface Visitor extends net.sf.jga.fn.Visitor {
132         public void visit(Divides host);
133     }
134 }
135
Popular Tags