/*
 *  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.ports.metadata.MDTransformer;
import com.rapidminer.operator.ports.metadata.MetaData;


/** An output port which forwards it output to a connected input port.
 *  Operators place their output into output ports which take care
 *  of forwarding the data to the input ports.
 * 
 * @author Simon Fischer
 */
public interface OutputPort extends Port {

	/** Connects to an input port.
	 *  @throws PortException if already connected. */
	public void connectTo(InputPort inputPort) throws PortException;
	
	/** Disconnects the OutputPort from its InputPort. 
	 *  Note: As a side effect, disconnecting ports may trigger PortExtenders removing these ports.
	 *  In order to avoid this behaviour, {@link #lock()} port first.
	 * @throws PortException if not connected. */
	public void disconnect() throws PortException;
	
	/** Delivers an object to the connected {@link InputPort} or ignores
	 *  it if the output port is not connected. */	 
	public void deliver(IOObject object);
	
	/** Returns the destination input port. */
	public InputPort getDestination();
	
	/** Does the same as {@link #deliver(Object)} except that only meta data is delivered.
	 *  This method is called by the Operator's {@link MDTransformer}. */
	public void deliverMD(MetaData md);	

	/** Asks the owning operator {@link com.rapidminer.operator.Operator#shouldAutoConnect(OutputPort)}. */
	public boolean shouldAutoConnect();
}