1 /*
2 * The contents of this file are subject to the BT "ZEUS" Open Source
3 * Licence (L77741), Version 1.0 (the "Licence"); you may not use this file
4 * except in compliance with the Licence. You may obtain a copy of the Licence
5 * from $ZEUS_INSTALL/licence.html or alternatively from
6 * http://www.labs.bt.com/projects/agents/zeus/licence.htm
7 *
8 * Except as stated in Clause 7 of the Licence, software distributed under the
9 * Licence is distributed WITHOUT WARRANTY OF ANY KIND, either express or
10 * implied. See the Licence for the specific language governing rights and
11 * limitations under the Licence.
12 *
13 * The Original Code is within the package zeus.*.
14 * The Initial Developer of the Original Code is British Telecommunications
15 * public limited company, whose registered office is at 81 Newgate Street,
16 * London, EC1A 7AJ, England. Portions created by British Telecommunications
17 * public limited company are Copyright 1996-9. All Rights Reserved.
18 *
19 * THIS NOTICE MUST BE INCLUDED ON ANY COPY OF THIS FILE
20 */
21
22
23
24 package zeus.rete;
25
26 import java.util.*;
27 import zeus.util.*;
28 import zeus.concepts.*;
29 import zeus.concepts.fn.*;
30
31
32 class TestNode extends PatternNode {
33 ValueFunction value = null;
34
35 TestNode(ReteEngine engine, ValueFunction value) {
36 super(engine);
37 this.value = value;
38 }
39 void evaluate(String path, int tag, int type, Vector input, Bindings b) {
40 // System.out.println("evaluating test " + path);
41 Assert.notFalse(type == SINGLE);
42 ValueFunction fn = value.resolve(b);
43 if ( !fn.isDeterminate() ) {
44 Core.USER_ERROR("Non-ground argument in Rete test expression \"" +
45 "(test " + value + ")\"");
46 return;
47 }
48
49 if ( !(fn instanceof LogicalFn) ) {
50 Core.USER_ERROR("Non-logical argument in Rete test expression \"" +
51 "(test " + value + ")\"");
52 return;
53 }
54 if ( ((LogicalFn)fn).evaluate() == LogicalFn.TRUE )
55 propagate(path,tag,input,b);
56 }
57 public boolean equals(Object any) {
58 if ( !(any instanceof TestNode) ) return false;
59 TestNode node = (TestNode)any;
60 return value.equals(node.value);
61 }
62 public String toString() {
63 return "TestNode(" + value + ")";
64 }
65 }