/*
 *  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 java.util.Collection;

import com.rapidminer.operator.IOObject;
import com.rapidminer.operator.ports.metadata.CompatibilityLevel;
import com.rapidminer.operator.ports.metadata.MetaData;
import com.rapidminer.operator.ports.metadata.Precondition;


/** A port that receives data from a connected output port. Operators query
 *  their input ports for data.
 * 
 * @author Simon Fischer
 */
public interface InputPort extends Port {

	/** Receives data from the output port. Throws an {@link PortException} if data
	 *  has already been set. (Called by {@link OuptutPort#deliver(Object)}.	 *   
	 */
	public void receive(IOObject object);

	/** Does the same as {@link #receive(Object)} but only with meta data. */
	public void receiveMD(MetaData metaData);

	/** Returns the meta data received by {@link #receiveMD(MetaData)}. */
	public MetaData getMetaData();

	//	/** Called by the OutputPort when it connects to this InputPort. */
	//	public void connect(OutputPort outputPort);

	/** Returns the output port to which this input port is connected. */
	public OutputPort getSource();

	/** Adds a precondition to this input port. */
	public void addPrecondition(Precondition precondition);

	/** Returns a collection (view) of all preconditions assigned to this InputPort. */
	public Collection<Precondition> getAllPreconditions();

	/** Checks all registered preconditions. */
	public void checkPreconditions();

	/** Returns true if the given input is compatible with the preconditions. */
	public boolean isInputCompatible(MetaData input, CompatibilityLevel level);

	/** Returns a human readable representation of the preconditions. */
	public String getPreconditionDescription();
	
	/**
	 * This will add the given listener to this port. It is informed whenever the method {@link #receiveMD(MetaData)} is called.
	 */
	public void registerMetaDataChangeListener(MetaDataChangeListener listener);
	
	/**
	 * Removes the given listener again.
	 */
	public void removeMetaDataChangeListener(MetaDataChangeListener listener);

}