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 import java.io.*;
30
31 /***
32
33 @author Simon Thompson
34 @since 1.1
35 */
36 public class ReadAction extends ReteAction{
37
38 /***
39 A rete action that reads a token off the defined DataReader from the
40 conflictSet getReaders() struct.
41 @see java.io.DataReader
42 */
43 public void executeAction (Action a, Info info) {
44 Hashtable readers = conflictHandler.getReaders();
45 ValueFunction var = ((ValueFunction)a.head).resolve(info.getBindings());
46 if ( var == null || var.getID() != ValueFunction.ID ) {
47 Core.USER_ERROR("Cannot resolve logical reader name '" + a.head + "' in action " + a);
48 return;
49 }
50 ValueFunction value = ((ValueFunction)a.sub_head).resolve(info.getBindings());
51 if ( value == null ) {
52 Core.USER_ERROR("Cannot resolve '" + a.sub_head + "' in action " + a);
53 return;
54 }
55
56 DataReader in = (DataReader)readers.get(((IdFn)var).getValue());
57 if ( in == null ) {
58 Core.USER_ERROR("Unknown reader '" + var + "' in " + a);
59 return;
60 }
61 try {
62 String input = null;
63 input = in.nextToken();
64 Bindings bind = info.getBindings();
65
66 if ( input == null )
67 Core.USER_ERROR("End of file reached while reading '" + var + "'");
68 else if ( Misc.isLong(input) )
69 bind.set(value,new IntFn(input));
70 else if ( Misc.isDouble(input) )
71 bind.set(value,new RealFn(input));
72 else
73 bind.set(value,new IdFn(input)); }
74 catch(IOException e) {
75 Core.USER_ERROR("IOException reading '" + var + "' in action " + a);
76 }
77 }
78
79
80 }