org.uclab.mm.kcl.ddkat.datapreprocessor.FeaturesSelector.java Source code

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Here is the source code for org.uclab.mm.kcl.ddkat.datapreprocessor.FeaturesSelector.java

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/**
 * Copyright [2017] [Maqbool Ali]
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.uclab.mm.kcl.ddkat.datapreprocessor;

import java.io.File;
import java.util.ArrayList;

import weka.filters.Filter;
import weka.filters.supervised.attribute.AttributeSelection;
import weka.attributeSelection.CfsSubsetEval;
import weka.attributeSelection.GreedyStepwise;
import weka.core.Instances;
import weka.core.converters.ArffSaver;
import weka.core.converters.CSVLoader;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// TODO: Auto-generated Javadoc
/**
 * This class filters the data to address the issue of the curse of dimensionality and then stores the filtered data.
 */
public class FeaturesSelector {

    /** The confirmation message. */
    private ArrayList<String> confirmationMessage;

    /** The Constant log. */
    private static final Logger log = LoggerFactory.getLogger(FeaturesSelector.class);

    /** base directory to store resource data files */
    private static final String BASE_DIR = System.getProperty("user.home") + "/DDKAT/resources/";

    /**
     * Constructor to instantiate a new FeaturesSelector object.
     *
     * @throws Exception the exception
     */
    public FeaturesSelector() throws Exception {

        filterData();
    }

    /**
     * Method to filter the input data using GreedyStepwise approach.
     *
     * @throws Exception the exception
     */
    public void filterData() throws Exception {

        this.confirmationMessage = new ArrayList<String>();

        Instances inputData, outputData;
        String inputFile = BASE_DIR + "OriginalDataSet.csv";

        // load CSV file
        CSVLoader fileLoader = new CSVLoader();
        fileLoader.setSource(new File(inputFile));
        inputData = fileLoader.getDataSet();

        inputData.setClassIndex(inputData.numAttributes() - 1);
        AttributeSelection filter = new AttributeSelection();
        CfsSubsetEval eval = new CfsSubsetEval();
        GreedyStepwise search = new GreedyStepwise();
        search.setSearchBackwards(true);
        filter.setEvaluator(eval);
        filter.setSearch(search);
        filter.setInputFormat(inputData);
        outputData = Filter.useFilter(inputData, filter);

        int indices = outputData.numAttributes();
        String selectedAttributesString = "";
        for (int i = 0; i < indices; i++) {
            selectedAttributesString += "\n" + outputData.attribute(i).toString() + ", ";
        }
        selectedAttributesString = selectedAttributesString.substring(0, selectedAttributesString.length() - 2);

        saveFilteredData(inputFile, outputData);

    }

    /**
     * Method to store the filtered data.
     *
     * @param filePath the file path
     * @param outputData the output data
     * @throws Exception the exception
     */
    public void saveFilteredData(String filePath, Instances outputData) throws Exception {

        // save ARFF file
        String outputFile = filePath.substring(0, filePath.lastIndexOf('/'));
        outputFile = outputFile + "/ProcessedDataSet.arff";
        log.info("Output file : " + outputFile);

        ArffSaver saver = new ArffSaver();
        saver.setInstances(outputData);
        saver.setFile(new File(outputFile));
        saver.writeBatch();

        String confirmationMessageStr = "Data is successfully filtered and is stored at : " + outputFile;
        log.info(confirmationMessageStr);
        this.confirmationMessage.add(confirmationMessageStr);
    }

    /**
     * Method to get the confirmation message of data filtration.
     *
     * @return the confirmation message
     */
    public ArrayList<String> getConfirmationMessage() {
        return confirmationMessage;
    }

    /**
     * Method to set the confirmation message of data filtration.
     *
     * @param confirmationMessage the new confirmation message
     */
    public void setConfirmationMessage(ArrayList<String> confirmationMessage) {
        this.confirmationMessage = confirmationMessage;
    }

}