/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2008 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.validation.significance;

import java.util.LinkedList;
import java.util.List;

import com.rapidminer.operator.IOObject;
import com.rapidminer.operator.MissingIOObjectException;
import com.rapidminer.operator.Operator;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.UserError;
import com.rapidminer.operator.performance.PerformanceVector;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.parameter.ParameterTypeDouble;
import com.rapidminer.tools.math.SignificanceTestResult;


/**
 * Determines if the null hypothesis (all actual mean values are the same) holds
 * for the input performance vectors.
 * 
 * @author Ingo Mierswa
 * @version $Id: SignificanceTestOperator.java,v 1.5 2006/04/05 08:57:28
 *          ingomierswa Exp $
 */
public abstract class SignificanceTestOperator extends Operator {
	
	public static final String PARAMETER_ALPHA = "alpha";

	public SignificanceTestOperator(OperatorDescription description) {
		super(description);
	}

	/**
	 * Returns the result of the significance test for the given performance
	 * vector collection.
	 */
	public abstract SignificanceTestResult performSignificanceTest(PerformanceVector[] allVectors, double alpha) throws OperatorException;

	/**
	 * Returns the minimum number of performance vectors which can be compared
	 * by this significance test.
	 */
	public abstract int getMinSize();

	/**
	 * Returns the maximum number of performance vectors which can be compared
	 * by this significance test.
	 */
	public abstract int getMaxSize();

	/** Writes the attribute set to a file. */
	public IOObject[] apply() throws OperatorException {
		List<PerformanceVector> allVectors = new LinkedList<PerformanceVector>();
		boolean ok = true;
		while (ok) {
			try {
				PerformanceVector pv = getInput(PerformanceVector.class);
				allVectors.add(pv);
			} catch (MissingIOObjectException e) {
				ok = false;
			}
		}

		if (allVectors.size() < getMinSize()) {
			throw new UserError(this, 123, PerformanceVector.class, getMinSize() + "");
		}

		if (allVectors.size() > getMaxSize()) {
			throw new UserError(this, 124, PerformanceVector.class, getMaxSize() + "");
		}

		PerformanceVector[] allVectorsArray = new PerformanceVector[allVectors.size()];
		allVectors.toArray(allVectorsArray);
		SignificanceTestResult result = performSignificanceTest(allVectorsArray, getParameterAsDouble(PARAMETER_ALPHA));

		// create result array
		IOObject[] resultArray = new IOObject[allVectors.size() + 1];
		System.arraycopy(allVectorsArray, 0, resultArray, 0, allVectorsArray.length);
		resultArray[resultArray.length - 1] = result;
		return resultArray;
	}

	public Class<?>[] getInputClasses() {
		return new Class[] { PerformanceVector.class };
	}

	public Class<?>[] getOutputClasses() {
		return new Class[] { PerformanceVector.class, SignificanceTestResult.class };
	}

	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();
		types.add(new ParameterTypeDouble(PARAMETER_ALPHA, "The probability threshold which determines if differences are considered as significant.", 0.0d, 1.0d, 0.05d));
		return types;
	}
}