01: package org.ofbiz.rules.engine;
02:
03: /**
04: * <p><b>Title:</b> Atom
05: * <p><b>Description:</b> None
06: * <p>Copyright (c) 1999 Steven J. Metsker.
07: * <p>Copyright (c) 2001 The Open For Business Project - www.ofbiz.org
08: *
09: * <p>Permission is hereby granted, free of charge, to any person obtaining a
10: * copy of this software and associated documentation files (the "Software"),
11: * to deal in the Software without restriction, including without limitation
12: * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13: * and/or sell copies of the Software, and to permit persons to whom the
14: * Software is furnished to do so, subject to the following conditions:
15: *
16: * <p>The above copyright notice and this permission notice shall be included
17: * in all copies or substantial portions of the Software.
18: *
19: * <p>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20: * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21: * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
22: * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
23: * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT
24: * OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
25: * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26: *
27: * <br>
28: * <p>An Atom is a Structure that no terms.
29: * <p>
30: * For example, the following structure
31: * <blockquote><pre>
32: * city(denver, 5280);
33: * </pre></blockquote>
34: *
35: * is a fact that contains two atoms, "denver" and 5280.
36: *
37: * @author Steven J. Metsker
38: * @version 1.0
39: */
40: public class Atom extends Fact implements ComparisonTerm {
41:
42: /**
43: * Contructs an atom from the specified object.
44: *
45: * @param Object the functor for this atom
46: */
47: public Atom(Object functor) {
48: super (functor);
49: }
50:
51: /**
52: * Returns the functor if this structure.
53: *
54: * @return the functor if this structure
55: */
56: public Object eval() {
57: return functor;
58: }
59: }
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