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The core ELK Reasoner package

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/*
 * #%L
 * ELK Reasoner
 * 
 * $Id$
 * $HeadURL$
 * %%
 * Copyright (C) 2011 - 2012 Department of Computer Science, University of Oxford
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */
package org.semanticweb.elk.reasoner.reduction;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.semanticweb.elk.owl.interfaces.ElkClass;
import org.semanticweb.elk.reasoner.indexing.model.IndexedClass;
import org.semanticweb.elk.reasoner.indexing.model.IndexedClassExpression;
import org.semanticweb.elk.reasoner.saturation.SaturationState;
import org.semanticweb.elk.util.collections.ArrayHashSet;

/**
 * The intermediate state of the transitive reduction computation.
 * 
 * @param 
 *            the type of the root indexed class expression for which transitive
 *            reduction needs to be computed
 * 
 * @param 
 *            the type of the transitive reduction job
 */
class TransitiveReductionState> {

	/**
	 * The transitive reduction job for which this state was created
	 */
	final J initiatorJob;

	/**
	 * The (current state of the) iterator over derived subsumers of the root
	 */
	final Iterator subsumerIterator;

	/**
	 * The total number of subsumers of the root
	 */
	final int subsumerCount;

	/**
	 * We collect subsumers equivalent to the root here
	 */
	final List rootEquivalent;

	/**
	 * A temporary subset of subsumers used to compute direct subsumers and
	 * their equivalent classes.
	 */
	final Set prunedSubsumers;

	/**
	 * Constructing the state for the initiator job. It is required that the
	 * saturation is already computed for the root of the initiator job.
	 * 
	 * @param initiatorJob
	 * @param saturationState
	 */
	TransitiveReductionState(J initiatorJob, SaturationState saturationState) {
		this.initiatorJob = initiatorJob;
		this.rootEquivalent = new ArrayList<>(1);
		this.prunedSubsumers = new ArrayHashSet<>(8);
		Set subsumers = saturationState.getContext(
				initiatorJob.getInput()).getComposedSubsumers();
		this.subsumerIterator = subsumers.iterator();
		this.subsumerCount = subsumers.size();
	}

}