package org.mandarax.reference;

/*
 * Copyright (C) 1999-2004 <a href="mailto:jens.dietrich@unforgettable.com">Jens Dietrich</a>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
import org.mandarax.kernel.InferenceEngine;
import org.mandarax.kernel.InferenceEngineFeatureDescriptions;
import org.mandarax.kernel.InferenceException;
import org.mandarax.kernel.Query;
import org.mandarax.kernel.ResultSet;

/**
 * Default inference engine. Instances are just wrappers. The actual inference engine is 
 * the latest stable recommended implementation. This is to support users selecting the 
 * right engine.
 * @author <A HREF="mailto:jens.dietrich@unforgettable.com">Jens Dietrich</A>
 * @version 3.3.1 <9 August 2004>
 * @since 2.1
 */
public class DefaultInferenceEngine implements InferenceEngine {
	private InferenceEngine delegate = new ResolutionInferenceEngine3();
	
	/**
	 * Get the feature descriptions.
	 * @return the feature descriptions
	 */
	public InferenceEngineFeatureDescriptions getFeatureDescriptions() {
		return delegate.getFeatureDescriptions();	
	}
	/**
	 * Answer a query, retrieve (multiple different) result.
	 * The cardinality contraints describe how many results should be computed. It is either
	 * <ol>
	 * <li> <code>ONE</code> - indicating that only one answer is expected
	 * <li> <code>ALL</code> - indicating that all answers should be computed
	 * <li> <code>an integer value greater than 0 indicating that this number of results expected
	 * </ol>
	 * @see #ONE
	 * @see #ALL
	 * @return the result set of the query
	 * @param query the query clause
	 * @param kb the knowledge base used to answer the query
	 * @param aCardinalityConstraint the number of results expected
	 * @param exceptionHandlingPolicy one of the constants definied in this class (BUBBLE_EXCEPTIONS,TRY_NEXT)
	 * @throws an InferenceException
	 */
	public ResultSet query(Query query, org.mandarax.kernel.KnowledgeBase kb, int aCardinalityConstraint, int exceptionHandlingPolicy) throws InferenceException {
		return delegate.query(query,kb,aCardinalityConstraint,exceptionHandlingPolicy);
	}
}
