/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2011 by Rapid-I and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapid-i.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.operator.ports.metadata;

import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.parameter.UndefinedParameterError;
/**
 * @author Simon Fischer
 */
public class ExampleSetPassThroughRule extends PassThroughRule {

	SetRelation relation;

	public ExampleSetPassThroughRule(InputPort inputPort, OutputPort outputPort, SetRelation attributeSetRelation) {
		super(inputPort, outputPort, false);
		this.relation = attributeSetRelation;
	}

	@Override
	public MetaData modifyMetaData(MetaData metaData) {
		if (metaData instanceof ExampleSetMetaData) {
			ExampleSetMetaData emd = (ExampleSetMetaData)metaData;
			if (relation != null) {
				emd.mergeSetRelation(relation);
			}
			try {
				return modifyExampleSet(emd);
			} catch (UndefinedParameterError e) {
				return emd;
			}

		} else {
			return metaData;
		}
	}

	/**
	 * This method might be used for convenience for slight modifications of the
	 * exampleSet like adding an attribute. Subclasses might override this method.
	 * @throws UndefinedParameterError 
	 */
	public ExampleSetMetaData modifyExampleSet(ExampleSetMetaData metaData) throws UndefinedParameterError {
		return metaData;
	}

}