Metrics.java

package org.kkarad.metrics;

import org.HdrHistogram.Histogram;

import gnu.trove.map.hash.TObjectLongHashMap;

public class Metrics {
    private static final Histogram histogram = new Histogram(3600000000000L, 3);
    private static TObjectLongHashMap<String> map = new TObjectLongHashMap<String>(1000, 0.5f, -1);

    private Metrics() {
    }

    public static void in(String id) {
        long now = System.nanoTime();
        map.put(id, now);
    }

    public static void out(String id) {
        long now = System.nanoTime();
        final long start = map.remove(id);
        if(start != -1) {
            histogram.recordValue(now - start);
        }
    }

    public static void printAndReset() {
        System.out.println("Recoded latencies (in usec) for pricing:");
        histogram.outputPercentileDistribution(System.out, 100.0);
        histogram.reset();
    }
}