import java.text.SimpleDateFormat;
import java.util.Random;

public class SampleGenerator {
    final private Random rnd = new Random();
    final private static SimpleDateFormat df = new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss");

    final String name;
    final double mean;
    final double variance;

    public SampleGenerator(String name, double mean, double variance) {
        this.name = name;
        this.mean = mean;
        this.variance = variance;
    }

    public double next() {
        return rnd.nextGaussian() * variance + mean;
    }

    public void log() {
        long currentTimeMillis = System.currentTimeMillis();
        System.out.println(String.format("TS: %s, sensor: %s,\t value: %2.0f",
                df.format(currentTimeMillis),
                name,
                next()));
    }

    /**
     * Start separate sampling thread
     * @param interval in milli-seconds
     */
    public void startSampleIntervals(int interval) {
        new Thread() {
            @Override
            public void run() {
                try {
                    while (true) {
                        Thread.sleep(interval);
                        log();
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    public static void main(String[] args) {

        SampleGenerator heartBeats = new SampleGenerator("heart 1", 70, 20);
        SampleGenerator heartBeats2 = new SampleGenerator("heart 2", 70, 20);
        SampleGenerator temp = new SampleGenerator("temp 1", 37, 5);

        heartBeats.startSampleIntervals(2000);
        heartBeats2.startSampleIntervals(4000);
        temp.startSampleIntervals(3000);
    }
}