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.kernel;
19:
20: /**
21: * Interface for abstract loop checkers. The inference engine passes a list of clauses
22: * that have been applied recently, and the loop checker decides whether this is
23: * an infinite loop or not. Implementing classes will not provide an algorithm
24: * that is theoretically correct (the checked list is finite, and there are recursive computations
25: * always applying the same rule that are longer than this list but terminate).
26: * But for certain (non mathematical) domains this will provide a correct loop checking.
27: * Therefor this is a typical 80/20 approach.
28: * @todo: investigate whether we should take unifications made into account
29: * @author <A href="http://www-ist.massey.ac.nz/JBDietrich" target="_top">Jens Dietrich</A>
30: * @version 3.4 <7 March 05>
31: * @since 1.3
32: */
33: public interface LoopCheckingAlgorithm {
34:
35: /**
36: * Indicates whether the list of applied clauses represents an infinite loop.
37: * @return a boolean
38: * @param appliedClauses a list
39: */
40: boolean isInfiniteLoop(java.util.List appliedClauses);
41: }
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