/*
 *  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;

import com.rapidminer.operator.ports.PortPairExtender;
import com.rapidminer.operator.ports.metadata.SubprocessTransformRule;

/**
 * A simple operator chain which can have an arbitrary number of inner
 * operators. The operators are subsequently applied and their output is used as
 * input for the succeeding operator. The input of the operator chain is used as
 * input for the first inner operator and the output of the last operator is
 * used as the output of the operator chain.
 * 
 * @author Ingo Mierswa, Simon Fischer
 */
public class SimpleOperatorChain extends OperatorChain {

	protected PortPairExtender inputExtender = new PortPairExtender("in", getInputPorts(), getSubprocess(0).getInnerSources());
	protected PortPairExtender outputExtender = new PortPairExtender("out", getSubprocess(0).getInnerSinks(), getOutputPorts());
	
	/** Creates an empty operator chain. */
	public SimpleOperatorChain(OperatorDescription description) {
		this(description, "Nested Chain");
	}

	/** This constructor allows subclasses to change the subprocess' name. */
	protected SimpleOperatorChain(OperatorDescription description, String subProcessName) {
		super(description, subProcessName);
		inputExtender.start();
		outputExtender.start();
		getTransformer().addRule(inputExtender.makePassThroughRule());
		getTransformer().addRule(new SubprocessTransformRule(getSubprocess(0)));
		getTransformer().addRule(outputExtender.makePassThroughRule());
	}
	
	@Override
	public void doWork() throws OperatorException {
		clearAllInnerSinks();
		inputExtender.passDataThrough();
		super.doWork();
		outputExtender.passDataThrough();
	}
}