01: // ============================================================================
02: // $Id: Generator.java,v 1.6 2006/11/30 05:03:42 davidahall Exp $
03: // Copyright (c) 2004-2005 David A. Hall
04: // ============================================================================
05: // The contents of this file are subject to the Common Development and
06: // Distribution License (CDDL), Version 1.0 (the License); you may not use this
07: // file except in compliance with the License. You should have received a copy
08: // of the the License along with this file: if not, a copy of the License is
09: // 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;
34:
35: import java.io.Serializable;
36:
37: /**
38: * Functor that takes no arguments and produces a single result. The result is
39: * not guaranteed to be the same each time the functor is called.
40: * <p>
41: * Copyright © 2004-2005 David A. Hall
42: * @author <a href="mailto:davidahall@users.sf.net">David A. Hall</a>
43: */
44:
45: abstract public class Generator<R> extends Functor<R> implements
46: Serializable, Visitable {
47: /**
48: * Generate one instance.
49: * @deprecated use fn() instead
50: */
51: abstract public R gen();
52:
53: /**
54: * Generate one instance.
55: */
56: public R fn() {
57: return gen();
58: }
59:
60: // -----------------
61: // Functor interface
62: // -----------------
63:
64: /**
65: * Executes the function and returns the result.
66: */
67: public R eval(Object... args) {
68: return fn();
69: }
70:
71: // -------------------
72: // Visitable interface
73: // -------------------
74:
75: /**
76: * No-op implementation of Visitable interface.
77: */
78: public void accept(Visitor v) {
79: }
80: }
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