01: /*
02: * Copyright (C) 1999-2004 <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</a>
03: *
04: * This library is free software; you can redistribute it and/or
05: * modify it under the terms of the GNU Lesser General Public
06: * License as published by the Free Software Foundation; either
07: * version 2 of the License, or (at your option) any later version.
08: *
09: * This library is distributed in the hope that it will be useful,
10: * but WITHOUT ANY WARRANTY; without even the implied warranty of
11: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12: * Lesser General Public License for more details.
13: *
14: * You should have received a copy of the GNU Lesser General Public
15: * License along with this library; if not, write to the Free Software
16: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17: */
18: package org.mandarax.util;
19:
20: import org.mandarax.kernel.*;
21:
22: /**
23: * Abstract clause iterator used by auto facts.
24: * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
25: * @version 3.4 <7 March 05>
26: * @since 1.2
27: */
28: abstract class AbstractAutoFactIterator extends AbstractClauseIterator {
29:
30: protected AutoFacts autofacts = null;
31:
32: /**
33: * Constructor.
34: * @param af the client object
35: */
36: public AbstractAutoFactIterator(AutoFacts af) {
37: autofacts = af;
38: }
39:
40: /**
41: * Perform a fact (e.g., resolve functions and predicates).
42: * Return true if the predicate (JPredicate) returns true!
43: * @param f the fact
44: * @param session a session
45: * @return the result of performing the fact
46: */
47: protected boolean perform(Fact f, Session session) {
48: try {
49: return ((Boolean) f.resolve(session)).booleanValue();
50: } catch (Throwable t) {
51: return false;
52: }
53: }
54:
55: }
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