StatisticsStopWatch.java

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package jsettlers.common.logging;

import java.util.Collections;
import java.util.List;
import java.util.Vector;

/**
 * This class implements a simple stop watch that records the time in milliseconds and prints
 * the average, mean, min and max of all measured measurements.
 *
 * @author codingberlin
 */
public class StatisticsStopWatch extends StopWatch {

	private final List<Long> measurements = new Vector<Long>();

	@Override
	public long now() {
		return System.currentTimeMillis();
	}

	@Override
	protected String getUnit() {
		return "ms";
	}

	@Override
	public void stop(String leadingText) {
		measurements.add(getDiff());
		Collections.sort(measurements);
	}

	@Override
	public String toString() {
		if (measurements.isEmpty()) {
			return " -> no measurements taken yet";
		}
		return " -> number of measurements: " + measurements.size()
				+ ", min: " + measurements.get(0) + " " + getUnit()
				+ ", average: " + calculateAverage(measurements) + " " + getUnit()
				+ ", median: " + getMedian() + " " + getUnit()
				+ ", max: " + getMax() + " " + getUnit();
	}

	public long getMedian() {
		return measurements.get((int) Math.floor(measurements.size() / 2));
	}

	public long getMax() {
		return measurements.get(measurements.size() - 1);
	}

	private double calculateAverage(List<Long> measurements) {
		long sum = 0;
		if(!measurements.isEmpty()) {
			for (Long measurement : measurements) {
				sum += measurement;
			}
			return sum / measurements.size();
		}
		return sum;
	}
}