/*
 *  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.preprocessing.filter.attributes;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Example;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.MetaDataInfo;
import com.rapidminer.parameter.ParameterHandler;

/**
 * This class implements a no missing value filter for attributes. Attributes are filtered and hence be removed from 
 * exampleSet if there are missing values in one of the examples in this attribute.
 * 
 * @author Sebastian Land, Ingo Mierswa
 */
public class NoMissingValuesAttributeFilter extends AbstractAttributeFilterCondition {

	public MetaDataInfo isFilteredOutMetaData(AttributeMetaData attribute, ParameterHandler handler) {
		switch (attribute.containsMissingValues()) {
		case YES:
			return MetaDataInfo.YES;
		case NO:
			return MetaDataInfo.NO;
		default:
			return MetaDataInfo.UNKNOWN;
		}
	}

	@Override
	public boolean isNeedingScan() {
		return true;
	}

	public ScanResult beforeScanCheck(Attribute attribute) {
		return ScanResult.UNCHECKED;
	}

	@Override
	public ScanResult check(Attribute attribute, Example example) {
		if (Double.isNaN(example.getValue(attribute)))
			return ScanResult.REMOVE;
		else // if is not NAN: Needs to check next one
			return ScanResult.UNCHECKED;
	}
}