missingvaluereplenishment.java

著名的开源仿真软件yale

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2002, 2003
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.operator;

import edu.udo.cs.yale.operator.parameter.*;
import edu.udo.cs.yale.example.ExampleSet;
import edu.udo.cs.yale.example.ExampleReader;
import edu.udo.cs.yale.example.Example;
import edu.udo.cs.yale.example.Attribute;
import edu.udo.cs.yale.tools.LogService;

import java.util.List;
import java.util.HashMap;
import java.util.Map;
import java.util.Iterator;

/** Replaces missing values in examples. If a value is missing, it is replaced by one of the
 *  functions minimum, maximum, average, and none, which is applied to the non missing attribute
 *  values of the example set. None means, that the value is not replaced.
 *  The function can be selected using the parameter list <code>columns</code>. If an attribute's
 *  name appears in this list as a key, the value is used as the function name. If the attribute's
 *  name is not in the list, the function specified by the <code>default</code> parameter is used.
 *
 *  @yale.xmlclass MissingValueReplenishment
 *  @author Ingo, Simon
 *  @version $Id: MissingValueReplenishment.java,v 2.2 2003/04/04 11:59:27 fischer Exp $
 */
public class MissingValueReplenishment extends Operator {

    private static final Class[] INPUT_CLASSES = { ExampleSet.class };
    private static final Class[] OUTPUT_CLASSES = { ExampleSet.class };

    public static final int NONE    = 0;
    public static final int MINIMUM = 1;
    public static final int MAXIMUM = 2;
    public static final int AVERAGE = 3;

    public static final String[] REP_NAMES = { "none", "minimum", "maximum", "average" };

    private Map replenishments = new HashMap();

    private int deflt;

    public void initApply() throws OperatorException {
	super.initApply();
	replenishments = new HashMap();

	deflt = getParameterAsInt("default");

	List columns = getParameterList("columns");
	Iterator i = columns.listIterator();
	while (i.hasNext()) {
	    Object[] pair = (Object[])i.next();
	    replenishments.put((String)pair[0], (Integer)pair[1]);
	    LogService.logMessage("MissingValueReplenishment: Replenish missing values in column " + pair[0] +
				  " with the " + pair[1] + " of the column.", LogService.MINIMUM);
	}
	LogService.logMessage("MissingValueReplenishment: Replenish all other missing values with the " + REP_NAMES[deflt] +
			      " of the column.", LogService.MINIMUM);
    }

    public IOObject[] apply() throws OperatorException {

        // get the input example set
	IOContainer input = getInput();
	ExampleSet eSet = (ExampleSet) input.getInput(ExampleSet.class);
	
	ExampleReader reader = eSet.getExampleReader();

	while (reader.hasNext()) {

	    Example example = reader.next();
	    for (int i = 0; i < example.getNumberOfAttributes(); i++) {
		if (Double.isNaN(example.getValue(i))) {
		    example.setValue(i, getReplenishmentValue(example.getAttribute(i)));
		}
	    }
	}

	return new IOObject[] { eSet };
    }

    /** Replaces tha values */
    private double getReplenishmentValue(Attribute attribute) {
	int rep = deflt;
	Object repObject = replenishments.get(attribute.getName());
	if (repObject != null) rep = ((Integer)repObject).intValue();
	switch (rep) {
	case NONE:
	    return Double.NaN;
	case MINIMUM:
	    return attribute.getMinimum();
	case MAXIMUM:
	    return attribute.getMaximum();
	case AVERAGE:
	    return attribute.getAverage();
	default:
	    LogService.logMessage("MissingValueReplenishment: Has not replenish the missing value. Leave it to NaN.", LogService.WARNING);
	    return Double.NaN;
	}
    }

    
    public Class[] getOutputClasses() { return OUTPUT_CLASSES; }
    public Class[] getInputClasses() { return INPUT_CLASSES; }

    public List getParameterTypes() {
	List types = super.getParameterTypes();
	types.add(new ParameterTypeCategory("default", "Function to apply to all columns that are not explicitliy specified by parameter 'columns'.", REP_NAMES, NONE));
	types.add(new ParameterTypeList("columns", "List of replacement functions for each column.", new ParameterTypeCategory("replace_with", "The key is the attribute name. The value is the name of function used to replace the missing value.", REP_NAMES, AVERAGE)));
	return types;
    }
}