/*
 *  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;

import com.rapidminer.operator.SimpleProcessSetupError;
import com.rapidminer.operator.ProcessSetupError.Severity;
import com.rapidminer.operator.ports.metadata.MDTransformationRule;
import com.rapidminer.operator.ports.metadata.MetaData;

/**
 * This extender is just for operators which don't have any real input. It just should ensure the
 * correct execution order. And throw a warning if nothing is connected.
 * @author Sebastian Land
 *
 */
public class DummyPortPairExtender extends PortPairExtender {

	public DummyPortPairExtender(String name, InputPorts inPorts, OutputPorts outPorts) {
		super(name, inPorts, outPorts);
	}


	/** The generated rule copies all meta data from the generated input ports to all generated output ports.
	 * Unlike the PortPairExtender, it warns if nothing is connected. */
	@Override
	public MDTransformationRule makePassThroughRule() {
		return new MDTransformationRule() {
			@Override
			public void transformMD() {
				boolean somethingConnected = false;
				for (PortPair pair : getManagedPairs()) {
					// testing if connected for execution order
					somethingConnected |= pair.getInputPort().isConnected() || pair.getOutputPort().isConnected();
					// transforming meta data.	
					MetaData inData = pair.getInputPort().getMetaData();
					if (inData != null) {
						inData = transformMetaData(inData.clone());
						inData.addToHistory(pair.getOutputPort());
						pair.getOutputPort().deliverMD(inData);
					} else {
						pair.getOutputPort().deliverMD(null);
					}
				}
				if (!somethingConnected) {
					PortOwner owner = getManagedPairs().get(0).getInputPort().getPorts().getOwner();
					owner.getOperator().addError(new SimpleProcessSetupError(Severity.WARNING, owner, "execution_order_undefined"));
				}
			}
		};
	}
}