/*
 *  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 java.util.Iterator;
import java.util.List;
import java.util.Set;

import com.rapidminer.example.Attribute;
import com.rapidminer.example.Attributes;
import com.rapidminer.example.ExampleSet;
import com.rapidminer.operator.OperatorDescription;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.annotation.ResourceConsumptionEstimator;
import com.rapidminer.operator.features.selection.AbstractFeatureSelection;
import com.rapidminer.operator.ports.metadata.AttributeMetaData;
import com.rapidminer.operator.ports.metadata.ExampleSetMetaData;
import com.rapidminer.operator.ports.metadata.MetaData;
import com.rapidminer.operator.tools.AttributeSubsetSelector;
import com.rapidminer.parameter.ParameterType;
import com.rapidminer.tools.OperatorResourceConsumptionHandler;


/**
 * <p>This operator filters the attributes of an exampleSet. Therefore, different conditions may be selected as 
 * parameter and only attributes fulfilling this condition are kept. The rest will be removed from the exampleSet
 * The conditions may be inverted.
 * The conditions are tested over all attributes and for every attribute over all examples. For example the
 * numeric_value_filter with the parameter string "> 6" will keep all nominal attributes and all numeric attributes
 * having a value of greater 6 in every example. A combination of conditions is possible: "> 6 ANDAND < 11" or "<= 5 || < 0".
 * But ANDAND and || must not be mixed. Please note that ANDAND has to be replaced by two ampers ands.</p>

 * <p>The attribute_name_filter keeps all attributes which names match the given regular expression.
 * The nominal_value_filter keeps all numeric attribute and all nominal attributes containing at least one of specified 
 * nominal values. "rainy ANDAND cloudy" would keep all attributes containing at least one time "rainy" and one time "cloudy".
 * "rainy || sunny" would keep all attributes containing at least one time "rainy" or one time "sunny". ANDAND and || are not
 * allowed to be mixed. And again, ANDAND has to be replaced by two ampers ands.</p>
 *  
 * @author Sebastian Land, Ingo Mierswa
 */
public class AttributeFilter extends AbstractFeatureSelection {

	private final AttributeSubsetSelector attributeSelector = new AttributeSubsetSelector(this, getExampleSetInputPort());

	public AttributeFilter(OperatorDescription description) {
		super(description);

	}
	

	@Override
	protected MetaData modifyMetaData(ExampleSetMetaData metaData) {
		ExampleSetMetaData subset = attributeSelector.getMetaDataSubset(metaData, true);
		Iterator<AttributeMetaData> amdIterator = metaData.getAllAttributes().iterator();
		while (amdIterator.hasNext()) {
			AttributeMetaData amd = amdIterator.next();
			AttributeMetaData subsetAMD = subset.getAttributeByName(amd.getName());
			if (subsetAMD == null) {
				amdIterator.remove();
			}
		}
		return metaData;
	}

	@Override
	public ExampleSet apply(ExampleSet exampleSet) throws OperatorException {		 
		Attributes attributes = exampleSet.getAttributes();
		Set<Attribute> attributeSubset = attributeSelector.getAttributeSubset(exampleSet, true);
		Iterator<Attribute> r = attributes.allAttributes();
		while (r.hasNext()) {
			Attribute attribute = r.next();
			if (!attributeSubset.contains(attribute))
				r.remove();
		}
		return exampleSet;
	}


	@Override
	public List<ParameterType> getParameterTypes() {
		List<ParameterType> types = super.getParameterTypes();		
		types.addAll(attributeSelector.getParameterTypes());
		return types;
	}
	
	@Override
	public ResourceConsumptionEstimator getResourceConsumptionEstimator() {
		return OperatorResourceConsumptionHandler.getResourceConsumptionEstimator(getInputPort(), AttributeFilter.class, attributeSelector);
	}
}