001/* Copyright (C) 2013 TU Dortmund
002 * This file is part of LearnLib, http://www.learnlib.de/.
003 * 
004 * LearnLib is free software; you can redistribute it and/or
005 * modify it under the terms of the GNU Lesser General Public
006 * License version 3.0 as published by the Free Software Foundation.
007 * 
008 * LearnLib is distributed in the hope that it will be useful,
009 * but WITHOUT ANY WARRANTY; without even the implied warranty of
010 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
011 * Lesser General Public License for more details.
012 * 
013 * You should have received a copy of the GNU Lesser General Public
014 * License along with LearnLib; if not, see
015 * <http://www.gnu.de/documents/lgpl.en.html>.
016 */
017package de.learnlib.cache.mealy;
018
019import java.util.Collection;
020
021import net.automatalib.automata.transout.MealyMachine;
022import net.automatalib.incremental.mealy.IncrementalMealyBuilder;
023import net.automatalib.words.Word;
024import net.automatalib.words.WordBuilder;
025import de.learnlib.api.EquivalenceOracle;
026import de.learnlib.api.EquivalenceOracle.MealyEquivalenceOracle;
027import de.learnlib.oracles.DefaultQuery;
028
029/**
030 * An {@link EquivalenceOracle} that tests an hypothesis for consistency with the
031 * contents of a {@link MealyCacheOracle}.
032 * 
033 * @author Malte Isberner <malte.isberner@gmail.com>
034 *
035 * @param <I> input symbol class
036 * @param <O> output symbol class
037 */
038public class MealyCacheConsistencyTest<I, O> implements
039                MealyEquivalenceOracle<I,O> {
040        
041        private final IncrementalMealyBuilder<I, O> incMealy;
042        
043        /**
044         * Constructor.
045         * @param incMealy the {@link IncrementalMealyBuilder} data structure underlying the
046         * cache.
047         */
048        public MealyCacheConsistencyTest(IncrementalMealyBuilder<I, O> incMealy) {
049                this.incMealy = incMealy;
050        }
051
052        /*
053         * (non-Javadoc)
054         * @see de.learnlib.api.EquivalenceOracle#findCounterExample(java.lang.Object, java.util.Collection)
055         */
056        @Override
057        public DefaultQuery<I, Word<O>> findCounterExample(
058                        MealyMachine<?, I, ?, O> hypothesis, Collection<? extends I> inputs) {
059                Word<I> w = incMealy.findSeparatingWord(hypothesis, inputs, false);
060                if(w == null)
061                        return null;
062                WordBuilder<O> wb = new WordBuilder<O>(w.length());
063                incMealy.lookup(w, wb);
064                DefaultQuery<I,Word<O>> result = new DefaultQuery<>(w);
065                result.answer(wb.toWord());
066                return result;
067        }
068
069}