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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.*; 
26  import zeus.concepts.fn.*;
27  import zeus.util.*;
28  /*** 
29      
30      @author Simon Thompson
31      @since 1.1
32      */
33  public class  RetractAction extends ReteAction {
34      
35      /***
36          Action that retracts a fact from a zeus.concepts.ResourceDb base
37          */
38      public void executeAction (Action a, Info info) { 
39                   for(int j = 0; j < a.items.size(); j++ ) {
40                      ValueFunction var = (ValueFunction)a.items.elementAt(j);
41                      ValueFunction type_var = var.resolve(info.getBindings());
42                      // type == 3 and id = 1... I'm not sure what this test is for, but it always fails... 
43                    System.out.println ("type_var.getID() == " + type_var.getID()); 
44                      System.out.println ("ValueFunction.TYPE == " + ValueFunction.TYPE); 
45                      Assert.notFalse(type_var.getID() == ValueFunction.TYPE);
46                      boolean found = false;
47                      for(int k = 0; ! found && k < info.getInput().size(); k++ ) {
48                          Fact f1 = (Fact)info.getInput().elementAt(k);
49                          found = (f1.functor()).equals(type_var);
50                          if ( found ) {
51                              Core.DEBUG(2," <== " + f1);
52                              retract(f1);
53                              }// end if 
54                          } // end for
55                       Assert.notFalse(found);
56                  }// end for 
57      }
58      
59      
60      
61      private void retract(Fact f1) {
62        if ( context == null )
63           engine.update(Node.REMOVE,f1);
64        else
65           context.ResourceDb().del(f1);
66     }
67      
68      
69  }