package com.zetcode;

import com.opencsv.CSVReader;

import com.opencsv.CSVReaderBuilder;

import java.io.IOException;

import java.io.Reader;

import java.nio.file.Files;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.List;

import org.apache.commons.cli.CommandLine;

import org.apache.commons.cli.CommandLineParser;

import org.apache.commons.cli.DefaultParser;

import org.apache.commons.cli.HelpFormatter;

import org.apache.commons.cli.Options;

import org.apache.commons.cli.ParseException;

import org.apache.commons.lang3.ArrayUtils;

import org.apache.commons.math3.stat.StatUtils;

/**

* MyStatsApp is a simple console application which computes

* basic statistics of a series of data values. The application takes

* a file of data as its single argument.

*

* @author janbodnar

*/

public class MyStatsApp {

/**

* Runs the application

*

* @param args an array of String arguments to be parsed

*/

public void run(String[] args) {

CommandLine line = parseArguments(args);

if (line.hasOption("filename")) {

System.out.println(line.getOptionValue("filename"));

String fileName = line.getOptionValue("filename");

double[] data = readData(fileName);

calculateAndPrintStats(data);

} else {

printAppHelp();

}

}

/**

* Parses application arguments

*

* @param args

* @return <code>CommandLine</code> which represents a list of application

* arguments.

*/

private CommandLine parseArguments(String[] args) {

Options options = getOptions();

CommandLine line = null;

CommandLineParser parser = new DefaultParser();

try {

line = parser.parse(options, args);

} catch (ParseException ex) {

System.err.println(ex);

printAppHelp();

System.exit(1);

}

return line;

}

/**

* Reads application data from a file

*

* @param fileName

* @return array of double values

*/

private double[] readData(String fileName) {

List<Double> data = new ArrayList();

double[] mydata = null;

try (Reader reader = Files.newBufferedReader(Paths.get(fileName));

CSVReader csvReader = new CSVReaderBuilder(reader).build()) {

String[] nextLine;

while ((nextLine = csvReader.readNext()) != null) {

for (String e : nextLine) {

data.add(Double.parseDouble(e));

}

}

mydata = ArrayUtils.toPrimitive(data.toArray(new Double[data.size()]));

} catch (IOException ex) {

System.err.println(ex);

System.exit(1);

}

return mydata;

}

/**

* Generates application command line options

*

* @return application <code>Options</code>

*/

private Options getOptions() {

Options options = new Options();

options.addOption("f", "filename", true, "file name to load data from");

return options;

}

/**

* Prints application help

*/

private void printAppHelp() {

Options options = getOptions();

HelpFormatter formatter = new HelpFormatter();

formatter.printHelp("JavaStatsEx", options, true);

}

/**

* Calculates and prints data statistics

*

* @param data input data

*/

private void calculateAndPrintStats(double[] data) {

System.out.format("Geometric mean: %f%n", StatUtils.geometricMean(data));

System.out.format("Arithmetic mean: %f%n", StatUtils.mean(data));

System.out.format("Max: %f%n", StatUtils.max(data));

System.out.format("Min: %f%n", StatUtils.min(data));

System.out.format("Sum: %f%n", StatUtils.sum(data));

System.out.format("Variance: %f%n", StatUtils.variance(data));

}

}