/*
 *  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.metadata;

/** This precondition checks whether the delivered object is of a given type
 *  or a collection of the given type (or a collection of such collections etc.).
 * 
 * @author Simon Fischer
 *
 */
public class CollectionPrecondition implements Precondition {

	private final Precondition nestedPrecondition;
	
	public CollectionPrecondition(Precondition precondition) {
		this.nestedPrecondition = precondition;
	}

	@Override
	public void assumeSatisfied() {
		nestedPrecondition.assumeSatisfied();
	}

	@Override
	public void check(MetaData md) {
		if (md != null) {
			if (md instanceof CollectionMetaData) {
				check(((CollectionMetaData)md).getElementMetaData());
				return;
			}
		}
		nestedPrecondition.check(md);
	}

	@Override
	public String getDescription() {
		return nestedPrecondition + " (collection)"; 
	}

	@Override
	public boolean isCompatible(MetaData input, CompatibilityLevel level) {
		if (input instanceof CollectionMetaData) {
			return isCompatible(((CollectionMetaData)input).getElementMetaData(), level);
		} else {
			return nestedPrecondition.isCompatible(input, level);
		}
	}

	@Override
	public MetaData getExpectedMetaData() {
		return new CollectionMetaData(nestedPrecondition.getExpectedMetaData());
	}

}