SingleLabelTermination.java

/**
 * Copyright (C) 2001-2017 by RapidMiner and the contributors
 * 
 * Complete list of developers available at our web site:
 * 
 * http://rapidminer.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.learner.tree;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.example.ExampleSet;

import java.util.Iterator;


/**
 * This criterion terminates if only one single label is left.
 * 
 * @author Sebastian Land, Ingo Mierswa
 */
public class SingleLabelTermination implements Terminator {

	public SingleLabelTermination() {}

	@Override
	public boolean shouldStop(ExampleSet exampleSet, int depth) {
		Attribute label = exampleSet.getAttributes().getLabel();
		Iterator<Example> iterator = exampleSet.iterator();
		if (label != null && iterator.hasNext()) {
			double singleValue = iterator.next().getValue(label);
			while (iterator.hasNext()) {
				if (iterator.next().getValue(label) != singleValue) {
					return false;
				}
			}
		}
		return true;
	}
}