Repository /Debellor/debellor-1.0.jar:org.debellor.rseslib.DataConverter

/*
 *  Debellor
 *
 *  Copyright (C) 2008-2009 by Marcin Wojnarski
 *
 *  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 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package org.debellor.rseslib;

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;

import org.debellor.core.DataObject;
import org.debellor.core.DataType;
import org.debellor.core.Sample;
import org.debellor.core.Sample.SampleType;
import org.debellor.core.data.DataVector;
import org.debellor.core.data.NumericFeature;
import org.debellor.core.data.SymbolicFeature;
import org.debellor.core.data.DataVector.DataVectorType;
import org.debellor.core.exception.data.DataCastException;
import org.debellor.core.exception.data.DataException;

import rseslib.structure.attribute.ArrayHeader;
import rseslib.structure.attribute.Header;
import rseslib.structure.attribute.NominalAttribute;
import rseslib.structure.data.DoubleDataObject;


/**
 * Conversion of data structures between Rseslib and Debellor representation.
 * 
 * @author Marcin Wojnarski
 *
 */
public class DataConverter {

	public static Header headerFrom(SampleType type) 
		throws RseslibConversionException 
	{
		// write Rseslib header to a string, then pass it to ArrayHeader constructor
		try {
			Writer buf = new StringWriter(1024);
			buf.write("missing_value ?\n");

			// write description of input features
			DataVectorType data = (DataVectorType) type.data;
			for(int i = 0; i < data.size(); i++)
				writeAttrHeader(buf, false, "a" + (i+1), data.get(i));

			// write description of decision feature
			if(type.hasDecision())
				writeAttrHeader(buf, true, "decision", type.decision);			

			LineNumberReader reader = new LineNumberReader(new StringReader(buf.toString()));
			return new ArrayHeader(reader);
		}
		catch(Exception e) {
			throw new RseslibConversionException(e);
		}
	}

	private static void writeAttrHeader(Writer header, boolean isDecision, String name, DataType attr)
		throws IOException, RseslibConversionException 
	{
		header.write(name + " ");
		if(isDecision)	header.write("decision");
		else 		header.write("conditional");
		header.write(",");
		if(attr.dataClass == NumericFeature.class)
			header.write("numeric");
		else if(attr.dataClass == SymbolicFeature.class)
			header.write("nominal");
		else
			throw new RseslibConversionException("Debellor to Rseslib conversion error. Unsupported feature type.");
		header.write("\n");
	}

	public static DoubleDataObject doubledataFrom(Sample sample, SampleType type, Header header) throws DataCastException 
	{
		DataVector data = (DataVector) sample.data;
		DoubleDataObject dd = new DoubleDataObject(header);
		
		// insert input features
		int i = 0;
		for(; i < data.size(); i++)
			if(data.isMissing(i))
				dd.set(i, Double.NaN);
			else
				dd.set(i, rseslibValueFrom(data.get(i), header.attribute(i)));
		
		// insert decision attribute at the end
		if(type.hasDecision())
			if(sample.decision == null)
				dd.set(i, Double.NaN);
			else
				dd.set(i, rseslibValueFrom((DataObject) sample.decision, header.attribute(i)));
		
		return dd;
	}

	private static double rseslibValueFrom(DataObject v, 
			rseslib.structure.attribute.Attribute rseslibAttr) throws DataCastException 
	{
		try {
			return v.asNumericFeature().value;
		}
		catch(DataCastException e) {}
		
		SymbolicFeature sv = v.asSymbolicFeature();
		rseslib.structure.attribute.NominalAttribute  nominalAttr =
			(rseslib.structure.attribute.NominalAttribute)  rseslibAttr;
		
		return nominalAttr.globalValueCode(sv.value);
	}

	public static DataObject attrFromRseslibValue(double v, DataType attrType) 
		throws DataException 
	{
		if(attrType.dataClass == NumericFeature.class)
			return new NumericFeature(v);
		return new SymbolicFeature(NominalAttribute.stringValue(v), attrType);
	}

}