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Java > Open Source Codes > net > sf > jga > fn > adaptor > Generate2nd


1 // ============================================================================
2 // $Id: Generate2nd.java,v 1.7 2006/01/08 00:52:25 davidahall Exp $
3 // Copyright (c) 2004-2005 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.adaptor;
34
35 import net.sf.jga.fn.BinaryFunctor;
36 import net.sf.jga.fn.Generator;
37 import net.sf.jga.fn.UnaryFunctor;
38
39 /**
40  * UnaryFunctor that uses a Generator to produce the 2nd argument to a given
41  * BinaryFunctor.
42  * <p>
43  * Copyright &copy; 2004-2005 David A. Hall
44  * @author <a HREF="mailto:davidahall@users.sf.net">David A. Hall</a>
45  */
46
47 public class Generate2nd<T1,T2,R> extends UnaryFunctor<T1,R> {
48     
49     static final long serialVersionUID = 8944237143829635388L;
50
51     // The Functor applied to each value generated
52 private BinaryFunctor<T1,T2,R> _fn;
53
54     // The Nested Generator
55 private Generator<T2> _gen;
56     
57     public Generate2nd(BinaryFunctor<T1,T2,R> fn, Generator<T2> gen) {
58         _fn = fn;
59         _gen = gen;
60     }
61
62     /**
63      * Returns the Functor that is invoked
64      */
65
66     public BinaryFunctor<T1,T2,R> getFunctor() { return _fn; }
67
68     /**
69      * Returns the generator that produces the 2nd argument.
70      */
71
72     public Generator<T2> getGenerator() { return _gen; }
73     
74     /**
75      * Returns the results of the functor, using the nested generator to
76      * produce the first argument.
77      */
78     public R fn(T1 arg) {
79         return _fn.fn(arg, _gen.gen());
80     }
81
82     /**
83      * Calls the Visitor's <code>visit(Generate2nd)</code> method, if it
84      * implements the nested Visitor interface.
85      */
86     public void accept(net.sf.jga.fn.Visitor v) {
87         if (v instanceof Generate2nd.Visitor)
88             ((Generate2nd.Visitor)v).visit(this);
89         else
90             v.visit(this);
91     }
92
93     // Object overrides
94
95     public String JavaDoc toString() {
96         return _fn+".generate2nd("+_gen+")";
97     }
98     
99     // Acyclic Visitor
100
101     /**
102      * Interface for classes that may interpret a <b>Generate2nd</b>
103      * functor.
104      */
105     public interface Visitor extends net.sf.jga.fn.Visitor {
106         public void visit(Generate2nd host);
107     }
108 }
109
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