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 package zeus.rete.action;
24 import zeus.rete.*;
25 import zeus.concepts.fn.*;
26 import zeus.concepts.*;
27 import zeus.util.*;
28 import java.util.*;
29 /***
30
31 @author Simon Thompson
32 @since 1.1
33 */
34 public class ModifyAction extends ReteAction{
35
36 /***
37 An action that gets a fact and then modifies it before putting it back
38 @see ReteAction
39 */
40 public void executeAction (Action a, Info info) {
41 ValueFunction type_var = ((VarFn)a.head).resolve(info.getBindings());
42 Assert.notFalse(type_var.getID() == ValueFunction.TYPE);
43 boolean found = false;
44 for(int k = 0; !found && k < info.getInput().size(); k++ ) {
45 Fact f1 = (Fact)info.getInput().elementAt(k);
46 found = (f1.functor()).equals(type_var);
47 if ( found ) {
48 Core.DEBUG(2," <== " + f1);
49 retract(f1);
50 Enumeration enum = a.table.keys();
51 while( enum.hasMoreElements() ) {
52 String attribute = (String)enum.nextElement();
53 ValueFunction value = (ValueFunction)a.table.get(attribute);
54 value = value.resolve(info.getBindings());
55 f1.setValue(attribute,value);
56 }
57 Core.DEBUG(2," ==> " + f1);
58 assertFact(f1);
59 }
60 }
61 Assert.notFalse(found);
62 }
63
64
65 private void retract(Fact f1) {
66 if ( context == null )
67 engine.update(Node.REMOVE,f1);
68 else
69 context.ResourceDb().del(f1);
70 }
71
72
73 public void assertFact(Fact f1) {
74 if ( context == null ) // i.e. a local engine
75 engine.update(Node.ADD,f1);
76 else
77 context.ResourceDb().add(f1);
78 }
79 }