/* Copyright 2009-2016 David Hadka
 *
 * This file is part of the MOEA Framework.
 *
 * The MOEA Framework 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 3 of the License, or (at your
 * option) any later version.
 *
 * The MOEA Framework 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 the MOEA Framework.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.moeaframework.analysis.collector;

import org.moeaframework.core.Algorithm;
import org.moeaframework.core.EpsilonBoxDominanceArchive;
import org.moeaframework.core.Indicator;

/**
 * Collects performance indicator values from an {@link Algorithm}.
 */
public class IndicatorCollector implements Collector {

	/**
	 * The performance indicator used by this collector.
	 */
	private final Indicator indicator;

	/**
	 * The algorithm instance used by this collector; or {@code null} if this 
	 * collector has not yet been attached.
	 */
	private final Algorithm algorithm;
	
	/**
	 * The ε-box dominance archive used to prune the approximation set
	 * to a desired resolution; or {@code null} if no such pruning is used.
	 */
	private final EpsilonBoxDominanceArchive archive;
	
	/**
	 * Constructs an unattached collector for recording performance indicator
	 * values from an algorithm.
	 * 
	 * @param indicator the performance indicator used by this collector
	 */
	public IndicatorCollector(Indicator indicator) {
		this(indicator, null, null);
	}
	
	/**
	 * Constructs an unattached collector for recording performance indicator
	 * values from an algorithm, with an ε-box dominance archive to
	 * prune the approximation set to a desired resolution.
	 * 
	 * @param indicator the performance indicator used by this collector
	 * @param archive the ε-box dominance archive used to prune the 
	 *        approximation set to a desired resolution; or {@code null} if 
	 *        no such pruning is used
	 */
	public IndicatorCollector(Indicator indicator, 
			EpsilonBoxDominanceArchive archive) {
		this(indicator, archive, null);
	}

	/**
	 * Constructs a collector for recording performance indicator values from
	 * the specified algorithm.
	 * 
	 * @param indicator the performance indicator used by this collector
	 * @param archive the ε-box dominance archive used to prune the 
	 *        approximation set to a desired resolution; or {@code null} if 
	 *        no such pruning is used
	 * @param algorithm the algorithm this collector records data from
	 */
	public IndicatorCollector(Indicator indicator, 
			EpsilonBoxDominanceArchive archive, Algorithm algorithm) {
		super();
		this.indicator = indicator;
		this.archive = archive;
		this.algorithm = algorithm;
	}

	@Override
	public void collect(Accumulator accumulator) {
		if (archive == null) {
			accumulator.add(indicator.getClass().getSimpleName(),
					indicator.evaluate(algorithm.getResult()));
		} else {
			archive.clear();
			archive.addAll(algorithm.getResult());
			
			accumulator.add(indicator.getClass().getSimpleName(),
					indicator.evaluate(archive));
		}
	}

	@Override
	public AttachPoint getAttachPoint() {
		return AttachPoint.isSubclass(Algorithm.class).and(
				AttachPoint.not(AttachPoint.isNestedIn(Algorithm.class)));
	}

	@Override
	public Collector attach(Object object) {
		return new IndicatorCollector(indicator, archive, (Algorithm)object);
	}

}