fr.lirmm.graphik.graal.forward_chaining.ChaseWithGRDAndUnfiers.java Source code

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Here is the source code for fr.lirmm.graphik.graal.forward_chaining.ChaseWithGRDAndUnfiers.java

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/*
 * Copyright (C) Inria Sophia Antipolis - Mditerrane / LIRMM
 * (Universit de Montpellier & CNRS) (2014 - 2015)
 *
 * Contributors :
 *
 * Clment SIPIETER <clement.sipieter@inria.fr>
 * Mlanie KNIG
 * Swan ROCHER
 * Jean-Franois BAGET
 * Michel LECLRE
 * Marie-Laure MUGNIER <mugnier@lirmm.fr>
 *
 *
 * This file is part of Graal <https://graphik-team.github.io/graal/>.
 *
 * This software is governed by the CeCILL  license under French law and
 * abiding by the rules of distribution of free software.  You can  use,
 * modify and/ or redistribute the software under the terms of the CeCILL
 * license as circulated by CEA, CNRS and INRIA at the following URL
 * "http://www.cecill.info".
 *
 * As a counterpart to the access to the source code and  rights to copy,
 * modify and redistribute granted by the license, users are provided only
 * with a limited warranty  and the software's author,  the holder of the
 * economic rights,  and the successive licensors  have only  limited
 * liability.
 *
 * In this respect, the user's attention is drawn to the risks associated
 * with loading,  using,  modifying and/or developing or reproducing the
 * software by the user in light of its specific status of free software,
 * that may mean  that it is complicated to manipulate,  and  that  also
 * therefore means  that it is reserved for developers  and  experienced
 * professionals having in-depth computer knowledge. Users are therefore
 * encouraged to load and test the software's suitability as regards their
 * requirements in conditions enabling the security of their systems and/or
 * data to be ensured and,  more generally, to use and operate it in the
 * same conditions as regards security.
 *
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL license and that you accept its terms.
 */
/**
* 
*/
package fr.lirmm.graphik.graal.forward_chaining;

import java.util.LinkedList;
import java.util.Queue;

import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import fr.lirmm.graphik.graal.api.core.AtomSet;
import fr.lirmm.graphik.graal.api.core.Rule;
import fr.lirmm.graphik.graal.api.core.Substitution;
import fr.lirmm.graphik.graal.api.forward_chaining.AbstractChase;
import fr.lirmm.graphik.graal.api.forward_chaining.ChaseException;
import fr.lirmm.graphik.graal.core.HashMapSubstitution;
import fr.lirmm.graphik.graal.core.Unifier;
import fr.lirmm.graphik.graal.forward_chaining.rule_applier.DefaultRuleApplier;
import fr.lirmm.graphik.graal.grd.GraphOfRuleDependencies;

/**
 * @author Clment Sipieter (INRIA) <clement@6pi.fr>
 *
 */
public class ChaseWithGRDAndUnfiers extends AbstractChase {

    private static final Logger LOGGER = LoggerFactory.getLogger(ChaseWithGRDAndUnfiers.class);

    private GraphOfRuleDependencies grd;
    private AtomSet atomSet;
    private Queue<Pair<Rule, Substitution>> queue = new LinkedList<Pair<Rule, Substitution>>();

    // /////////////////////////////////////////////////////////////////////////
    // CONSTRUCTOR
    // /////////////////////////////////////////////////////////////////////////

    public ChaseWithGRDAndUnfiers(GraphOfRuleDependencies grd, AtomSet atomSet) {
        super(new DefaultRuleApplier());
        this.grd = grd;
        this.atomSet = atomSet;
        for (Rule r : grd.getRules()) {
            this.queue.add(new ImmutablePair<Rule, Substitution>(r, new HashMapSubstitution()));
        }
    }

    // /////////////////////////////////////////////////////////////////////////
    // METHODS
    // /////////////////////////////////////////////////////////////////////////

    @Override
    public void next() throws ChaseException {
        Rule rule, unifiedRule;
        Substitution unificator;

        try {
            Pair<Rule, Substitution> pair = queue.poll();
            if (pair != null) {
                unificator = pair.getRight();
                rule = pair.getLeft();
                unifiedRule = Unifier.computeInitialAtomSetTermsSubstitution(rule.getBody()).createImageOf(rule);
                unifiedRule = unificator.createImageOf(unifiedRule);

                if (LOGGER.isDebugEnabled()) {
                    LOGGER.debug("Execute rule: " + rule + " with unificator " + unificator);
                }

                if (this.getRuleApplier().apply(unifiedRule, this.atomSet)) {
                    for (Integer e : this.grd.getOutgoingEdgesOf(rule)) {
                        Rule triggeredRule = this.grd.getEdgeTarget(e);
                        for (Substitution u : this.grd.getUnifiers(e)) {
                            if (LOGGER.isDebugEnabled()) {
                                LOGGER.debug("-- -- Dependency: " + triggeredRule + " with " + u);
                                LOGGER.debug("-- -- Unificator: " + u);
                            }
                            if (u != null) {
                                this.queue.add(new ImmutablePair<Rule, Substitution>(triggeredRule, u));
                            }
                        }
                    }
                }
            }
        } catch (Exception e) {
            throw new ChaseException("An error occur pending saturation step.", e);
        }
    }

    @Override
    public boolean hasNext() {
        return !queue.isEmpty();
    }

}