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Java > Open Source Codes > net > sf > jga > swing > GenericItemListener


1 // ============================================================================
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// $Id: GenericItemListener.java,v 1.5 2005/08/02 23:45:21 davidahall Exp $
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// Copyright (c) 2004-2005 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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// 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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// ============================================================================
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package net.sf.jga.swing;
33
34 import java.awt.event.ItemEvent JavaDoc;
35 import java.awt.event.ItemListener JavaDoc;
36 import net.sf.jga.fn.UnaryFunctor;
37 import net.sf.jga.fn.adaptor.ConstantUnary;
38 import net.sf.jga.fn.property.ArrayUnary;
39 import net.sf.jga.fn.property.InvokeMethod;
40 import net.sf.jga.fn.property.InvokeNoArgMethod;
41
42 /**
43  * Listener that will execute a given functor on every item event.
44  * <p>
45  * Copyright &copy; 2004-2005 David A. Hall
46  * @author <a HREF="mailto:davidahall@users.sf.net">David A. Hall</a>
47  */

48
49 public class GenericItemListener implements ItemListener JavaDoc {
50
51     /**
52      * Builds a listener invokes the given no-arg method every time an
53      * item event fires.
54      */

55
56     static public <T> GenericItemListener
57     buildListener(Class JavaDoc<T> type, T object, String JavaDoc methodName) {
58         return new GenericItemListener(
59                    new InvokeNoArgMethod<T,Object JavaDoc>(type,methodName)
60                         .compose(new ConstantUnary<ItemEvent JavaDoc,T>(object)));
61     }
62
63     /**
64      * Builds a listener that passes each item event it receives to the
65      * given method.
66      */

67
68     static public <T> GenericItemListener
69     buildEventListener(Class JavaDoc<T> type, T object, String JavaDoc methodName) {
70         return new GenericItemListener(
71                    new InvokeMethod<T,Object JavaDoc>(type,methodName,ItemEvent JavaDoc.class)
72                         .compose(new ConstantUnary<ItemEvent JavaDoc,T>(object),
73                                  new ArrayUnary<ItemEvent JavaDoc>()));
74     }
75
76     // The functor to execute
77
private UnaryFunctor<ItemEvent JavaDoc,?> _fn;
78         
79     /**
80      * Builds an item listener that executes the given functor for every
81      * item event it receives.
82      */

83     public GenericItemListener(UnaryFunctor<ItemEvent JavaDoc,?> fn) {
84         _fn = fn;
85     }
86
87     // -------------------------------------------------------------------------
88
// ItemListener interface
89
// -------------------------------------------------------------------------
90

91     /**
92      * Passes the item event to the functor given at construction. The
93      * result of the functor, if any, is discareded.
94      */

95     public void itemStateChanged(ItemEvent JavaDoc evt) {
96         _fn.fn(evt);
97     }
98
99 }
100
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