/*
 *  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 java.util.Collection;

import com.rapidminer.operator.ports.InputPort;
import com.rapidminer.operator.ports.OutputPort;
import com.rapidminer.operator.ports.OutputPorts;


/** A rule which copies meta data from one input port to several output ports.
 * 
 * @author Simon Fischer
 *
 */
public class OneToManyPassThroughRule implements MDTransformationRule {

	private final InputPort inputPort;
	private final Collection<OutputPort> outputPorts;

	public OneToManyPassThroughRule(InputPort inputPort, OutputPorts outputPorts) {
		this(inputPort, outputPorts.getAllPorts());
	}

	public OneToManyPassThroughRule(InputPort inputPort, Collection<OutputPort> outputPorts) {	
		this.inputPort = inputPort;
		this.outputPorts = outputPorts;
	}

	@Override
	public void transformMD() {		
		int i = 0;
		for (OutputPort outputPort : outputPorts) {
			MetaData metaData = inputPort.getMetaData();
			if (metaData != null) {
				metaData = metaData.clone();
				metaData.addToHistory(outputPort);
				outputPort.deliverMD(modifyMetaData(metaData, i));
			} else {
				outputPort.deliverMD(null);
			}
			i++;
		}
	}

	/** Modifies the received meta data before it is passed to the output. Can be used
	 *  if the transformation depends on parameters etc. The default implementation
	 *  just returns the original. Subclasses may safely modify the meta data, since
	 *  a copy is used for this method. 
	 * @param outputIndex TODO*/
	public MetaData modifyMetaData(MetaData unmodifiedMetaData, int outputIndex) {
		return unmodifiedMetaData;
	}
}