/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    Copyright (C) 2009-2010 Aristotle University of Thessaloniki, Thessaloniki, Greece
 */

package mulan.data;

import mulan.core.MulanRuntimeException;
import weka.core.DenseInstance;
import weka.core.Instance;
import weka.core.SparseInstance;

/**
 * Utility class for data related manipulation functions.
 * 
 * @author Jozef Vilcek
 */
public class DataUtils {
	
	/**
	 * Creates a new {@link Instance}. The actual type is determined based on passed instance object.
	 * @param typeProvider the instance from which type for new instance is determined
	 * @param weight the weight of a new instance
	 * @param attrValues attribute values for a new instance
	 * @return A new {@link Instance}.
	 */
	public static Instance createInstance(Instance typeProvider, double weight, double[] attrValues){
		if(typeProvider instanceof SparseInstance){
			return new SparseInstance(weight, attrValues);
		}else if(typeProvider instanceof DenseInstance){
			return new DenseInstance(weight, attrValues);
		}else {
			throw new MulanRuntimeException(
					String.format("Can not create a new Instance from supplied type '%s'.", 
							typeProvider.getClass().getName()));
		}
		
	}
	
	/**
	 * Creates a new {@link Instance}. The actual type is determined based on passed instance object.
	 * @param typeProvider the instance from which type for new instance is determined
	 * @param numAttributes number of attributes for new instance
	 * @return A new {@link Instance}.
	 */
	public static Instance createInstance(Instance typeProvider, int numAttributes){
		if(typeProvider instanceof SparseInstance){
			return new SparseInstance(numAttributes);
		}else if(typeProvider instanceof DenseInstance){
			return new DenseInstance(numAttributes);
		}else {
			throw new MulanRuntimeException(
					String.format("Can not create a new Instance from supplied type '%s'.", 
							typeProvider.getClass().getName()));
		}
	}

}