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


1 // ============================================================================
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// $Id: AndGenerator.java,v 1.8 2006/01/08 00:52:25 davidahall Exp $
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// Copyright (c) 2002-2005 David A. Hall
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// ============================================================================
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// The contents of this file are subject to the Common Development and
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// Distribution License (CDDL), Version 1.0 (the License); you may not use this
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// file except in compliance with the License. You should have received a copy
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// of the the License along with this file: if not, a copy of the License is
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// available from Sun Microsystems, Inc.
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//
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// http://www.sun.com/cddl/cddl.html
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//
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// From time to time, the license steward (initially Sun Microsystems, Inc.) may
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// publish revised and/or new versions of the License. You may not use,
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// distribute, or otherwise make this file available under subsequent versions
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// of the License.
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//
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// Alternatively, the contents of this file may be used under the terms of the
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// GNU Lesser General Public License Version 2.1 or later (the "LGPL"), in which
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// case the provisions of the LGPL are applicable instead of those above. If you
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// wish to allow use of your version of this file only under the terms of the
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// LGPL, and not to allow others to use your version of this file under the
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// terms of the CDDL, indicate your decision by deleting the provisions above
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// and replace them with the notice and other provisions required by the LGPL.
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// If you do not delete the provisions above, a recipient may use your version
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// of this file under the terms of either the CDDL or the LGPL.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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// ============================================================================
32

33 package net.sf.jga.fn.adaptor;
34
35 import net.sf.jga.fn.Generator;
36
37 /**
38  * Generator that performs a shortcircuit and operation using a given pair
39  * of Boolean Generators. When the first generator returns true, the second
40  * is not evaluated.
41  **/

42
43 public class AndGenerator extends Generator<Boolean JavaDoc> {
44
45     static final long serialVersionUID = 6260506966868219143L;
46     
47     // The two generators that are tested
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private Generator<Boolean JavaDoc> _first;
49     private Generator<Boolean JavaDoc> _second;
50     
51     /**
52      * Builds a AndGenerator functor, given the two functors that may be executed.
53      * @throws IllegalArgumentException if any of the functors is missing
54      */

55     public AndGenerator(Generator<Boolean JavaDoc> first, Generator<Boolean JavaDoc> second) {
56         if (first == null || second == null) {
57             throw new IllegalArgumentException JavaDoc("Two functors are required");
58         }
59         
60         _first = first;
61         _second = second;
62     }
63
64
65     public Generator<Boolean JavaDoc> getFirstFunctor() { return _first; }
66
67     public Generator<Boolean JavaDoc> getSecondFunctor() { return _second; }
68     
69     
70     public Boolean JavaDoc gen() {
71         return _first.gen() && _second.gen();
72     }
73
74     /**
75      * Calls the Visitor's <code>visit(AndGenerator)</code> method, if it
76      * implements the nested Visitor interface.
77      */

78     public void accept(net.sf.jga.fn.Visitor v) {
79         if (v instanceof AndGenerator.Visitor)
80             ((AndGenerator.Visitor)v).visit(this);
81         else
82             v.visit(this);
83     }
84
85     // Object overrides
86

87     public String JavaDoc toString() {
88         return _first +" && " +_second;
89     }
90     
91     // AcyclicVisitor
92

93     /**
94      * Interface for classes that may interpret an <b>AndGenerator</b> predicate.
95      */

96     public interface Visitor extends net.sf.jga.fn.Visitor {
97         public void visit(AndGenerator host);
98     }
99 }
100
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