entzik

public interface EnvObservation {
    public long getTimestamp();
    public void setTimeStamp(long timeStamp);
    public double getTemperature();
    public void setTemperature(double temperature);
    public double getHumidity();
    public void setHumidity(double humidity);
    public double getWindSpeed();
    public void setWindSpeed(double windSpeed);
}

entzik

Arrays.stream(dataset.metric1)
  .average()
  .getAsDouble()

entzik

ArrayList<DataItem> records;
.....
records.stream()
  .map(Record::getMetric1)
  .collect(Collectors.averagingDouble(d -> d))
  .doubleValue()

entzik

class DataItem {
  private long id;
  private double metric1;
  private double metric2;
  ...
  private double metricN;
  ...
  getters...
  setters...
}

entzik

class DataItemSet {
  private long[] id;
  private double[] metric1;
  private double[] metric2;
  ...
  private double[] metricN;

  getters...

  setters...

entzik

public class DoubleStreamAverageBenchmark {

    @State(Scope.Thread)
    public static class BenchmarkState {
        public double[] values;

        public BenchmarkState() {
            values  = new double[1000000];
            for (int i = 0; i < 1000000; i ++)
                values[i] = Math.random();

entzik

public class ObjectStreamAverageBenchmark {
    @State(Scope.Thread)
    public static class BenchmarkState {
        public ArrayList<Record> records;

        public BenchmarkState() {
            records = new ArrayList<>(1000000);
            for (int i = 0; i < 1000000; i ++)
                records.add(new Record(i, "name" + i, Math.random()));
        }