com.ibm.watson.developer_cloud.natural_language_classifier.v1.util.TrainingDataUtils.java Source code

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/**
 * Copyright 2015 IBM Corp. All Rights Reserved.
 *
 * 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 com.ibm.watson.developer_cloud.natural_language_classifier.v1.util;

import java.io.File;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVPrinter;
import org.apache.commons.csv.CSVRecord;

import com.ibm.watson.developer_cloud.natural_language_classifier.v1.model.TrainingData;
import com.ibm.watson.developer_cloud.util.Validate;

/**
 * Utility class to transform training data to CSV.
 */
public class TrainingDataUtils {

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

    /**
     * Converts a training like argument list to a CSV representation.
     * 
     * @param data
     *            the training data data
     * @return the string with the CSV representation for the training data
     */
    public static String toCSV(final TrainingData... data) {
        Validate.notEmpty(data, "data cannot be null or empty");

        StringWriter stringWriter = new StringWriter();
        try {
            CSVPrinter printer = new CSVPrinter(stringWriter, CSVFormat.EXCEL);
            for (TrainingData trainingData : data) {
                if (trainingData.getText() == null || trainingData.getClasses() == null
                        || trainingData.getClasses().isEmpty())
                    log.log(Level.WARNING, trainingData + " couldn't be converted to a csv record");
                else {
                    List<String> record = new ArrayList<String>();
                    record.add(trainingData.getText());
                    record.addAll(trainingData.getClasses());
                    printer.printRecord(record.toArray());
                }
            }
            printer.close();
        } catch (IOException e) {
            log.log(Level.SEVERE, "Error creating the csv", e);
        }

        return stringWriter.toString();
    }

    /**
     * Creates the training data list based on a csv file. 
     * File format needs to be UTF-8
     *
     * @param file            the CSV file
     * @param format the CSV format. See <a href="https://commons.apache.org/proper/commons-csv/apidocs/org/apache/commons/csv/CSVFormat.html">available formats</a>.
     * @return the training data list
     */
    public static List<TrainingData> fromCSV(final File file, CSVFormat format) {
        if (file == null || !file.exists())
            throw new IllegalArgumentException("file must exists and be different than null");

        List<TrainingData> trainingData = new ArrayList<TrainingData>();

        CSVParser parser;
        try {
            parser = CSVParser.parse(file, Charset.forName("UTF-8"), format);
            for (CSVRecord record : parser) {
                if (record.size() > 1) {
                    trainingData.add(getTrainigDataFromCSVRecord(record));
                } else {
                    log.warning(record.toString() + "skiped.");
                }
            }
        } catch (IOException e) {
            log.log(Level.SEVERE, "Error parsing the CSV", e);
        }

        return trainingData;
    }

    /**
     * Transform a {@link Record} into a {@link TrainingData}.
     *
     * @param record the record
     * @return the trainig data from csv record
     */
    private static TrainingData getTrainigDataFromCSVRecord(CSVRecord record) {
        TrainingData trainingData = new TrainingData();
        trainingData.setText(record.get(0));
        for (int i = 1; i < record.size(); i++) {
            trainingData.addClass(record.get(i));
        }
        return trainingData;
    }
}