/*
 *  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.IOObject;
import com.rapidminer.operator.IOObjectCollection;
import com.rapidminer.operator.ports.metadata.CollectionMetaData;
import com.rapidminer.operator.ports.metadata.MetaData;

/** This port pair extender offers the ability to collect data at its input
 *  ports over several iterations and deliver it to its output ports as a 
 *  collection.<br/>
 *  
 *  Usage: call {@link #reset()} before beginning the loop and {@link #collect()} in
 *  every iteration.
 * 
 * 
 * @author Simon Fischer
 */
public class CollectingPortPairExtender extends PortPairExtender {

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

	@Override
	protected MetaData transformMetaData(MetaData md) {
		return new CollectionMetaData(md);
	}

	/** Resets all output ports by delivering empty collection to all output ports for
	 *  which the input port is connected and clearing others. */
	public void reset() {
		for (PortPair pair : getManagedPairs()) {
			if (pair.getInputPort().isConnected()) {
				pair.getOutputPort().deliver(new IOObjectCollection<IOObject>());
			} else {
				pair.getOutputPort().clear(Port.CLEAR_DATA);
			}
		}
	}

	/** For all input ports that have data, this data is added to the collection currently assigned
	 *  to the output port. */
	@SuppressWarnings("unchecked")
	public void collect() {
		synchronized (this) {
			for (PortPair pair : getManagedPairs()) {
				IOObject data = pair.getInputPort().getAnyDataOrNull();
				if (data != null) {
					IOObject output = pair.getOutputPort().getAnyDataOrNull();
					if (output == null) { // first iteration
						IOObjectCollection<IOObject> collection = new IOObjectCollection<IOObject>();
						collection.add(data);
						pair.getOutputPort().deliver(collection);
					} else if (output instanceof IOObjectCollection){
						((IOObjectCollection<IOObject>)output).add(data);
						pair.getOutputPort().deliver(output); // necessary to trigger updates
					} else {
						pair.getOutputPort().getPorts().getOwner().getOperator().getLogger().warning("Cannot collect output at "+pair.getOutputPort().getSpec()+": data is of type " + output.getClass().getName()+ ".");
					}
				}
			}
		}
	}
}