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


1 // ============================================================================
2 // $Id: Generate.java,v 1.8 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.Generator;
36 import net.sf.jga.fn.UnaryFunctor;
37
38 /**
39  * Generator that wraps a UnaryFunctor around a nested Generator. The values
40  * produced by the nested generator are passed to the functor, and the results
41  * returned to the caller.
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 Generate<T,R> extends Generator<R> {
48     
49     static final long serialVersionUID = -7866951985301046565L;
50
51     // The Functor applied to each value generated
52 private UnaryFunctor<T,R> _fn;
53
54     // The Nested Generator
55 private Generator<T> _gen;
56     
57     public Generate(UnaryFunctor<T,R> fn, Generator<T> gen) {
58         _fn = fn;
59         _gen = gen;
60     }
61
62     /**
63      * Returns the UnaryFunctor that is applied to values returned by the
64      * nested Generator.
65      */
66     public UnaryFunctor<T,R> getFunctor() { return _fn; }
67
68     /**
69      * Returns the nested Generator;
70      */
71     public Generator<T> getGenerator() { return _gen; }
72     
73     /**
74      * Returns the results of the nested generator as modified by the functor.
75      */
76     public R gen() {
77         return _fn.fn(_gen.gen());
78     }
79     
80     /**
81      * Calls the Visitor's <code>visit(Generate)</code> method, if it
82      * implements the nested Visitor interface.
83      */
84     public void accept(net.sf.jga.fn.Visitor v) {
85         if (v instanceof Generate.Visitor)
86             ((Generate.Visitor)v).visit(this);
87         else
88             v.visit(this);
89     }
90
91     // Object overrides
92
93     public String JavaDoc toString() {
94         return _fn+".generate("+_gen+")";
95     }
96     
97     // Acyclic Visitor
98
99     /**
100      * Interface for classes that may interpret a <b>Generate</b>
101      * functor.
102      */
103     public interface Visitor extends net.sf.jga.fn.Visitor {
104         public void visit(Generate host);
105     }
106 }
107
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