How to use

getSnapshot

method

in

com.codahale.metrics.Histogram

  @Override
  public HistogramStatistics getStatistics() {
    return new DropwizardHistogramStatistics(dropwizardHistogram.getSnapshot());
  }
}

  public Map<String, Object> values() {
    Map<String, Object> m = new LinkedHashMap<>();
    m.putAll(counter.values());
    m.put("p50_" + name, Math.round(this.histogram.getSnapshot().getMedian()));
    m.put("p95_" + name, Math.round(this.histogram.getSnapshot().get95thPercentile()));
    m.put("p99_" + name, Math.round(this.histogram.getSnapshot().get99thPercentile()));
    m.put("p999_" + name, Math.round(this.histogram.getSnapshot().get999thPercentile()));
    return m;
  }
}

public static Map<String, Object> buildHistogramMap(Histogram h) {
  Map<String, Object> metrics = Maps.newHashMap();
  if (h == null) {
    return metrics;
  }
  Map<String, Object> time = Maps.newHashMap();
  time.put("max", h.getSnapshot().getMax());
  time.put("min", h.getSnapshot().getMin());
  time.put("mean", (long) h.getSnapshot().getMean());
  time.put("95th_percentile", (long) h.getSnapshot().get95thPercentile());
  time.put("98th_percentile", (long) h.getSnapshot().get98thPercentile());
  time.put("99th_percentile", (long) h.getSnapshot().get99thPercentile());
  time.put("std_dev", (long) h.getSnapshot().getStdDev());
  metrics.put("time", time);
  metrics.put("count", h.getCount());
  return metrics;
}

  @Override
  public int compare(Histogram o1, Histogram o2) {
    return Double.compare(o2.getSnapshot().getMean(), o1.getSnapshot().getMean());
  }
});

  public void writeValues(Histogram histogram, JsonGenerator jg) throws IOException {
    final Snapshot snapshot = histogram.getSnapshot();
    jg.writeNumberField("count", histogram.getCount());
    writeHistogramSnapshot(snapshot, jg);
  }
}

private void printHistogram(String name, Histogram histogram, int maxNameLength, StringBuilder sb) {
  sb.append(String.format("%" + maxNameLength + "s | ", name));
  sb.append(formatCount(histogram.getCount()));
  printHistogramSnapshot(histogram.getSnapshot(), sb);
  sb.append('\n');
}

private void reportHistogram(JsonGenerator json, String name, Histogram histogram) throws IOException {
 Snapshot snapshot = histogram.getSnapshot();
 json.writeFieldName(sanitize(name));
 json.writeStartObject();
 json.writeNumberField("count", histogram.getCount());
 writeSnapshot(json, snapshot);
 json.writeEndObject();
}

  @Override
  public Double getValue() {
    Snapshot snapshot = processedDurationHistogram.getSnapshot();
    double meanProcessTime = snapshot.getMean();
    int numProcessed = snapshot.getValues().length;
    return  (numProcessed * meanProcessTime) / timeUnit.toMillis(window);
  }
}

/**
 * Convert histogram snapshot.
 */
private SummaryMetricFamily fromHistogram(List<Map.Entry<MetricName, Histogram>> histogramsWithSameName) {
  final SummaryMetricFamily summaryMetricFamily = getSummaryMetricFamily(histogramsWithSameName, "");
  for (Map.Entry<MetricName, Histogram> entry : histogramsWithSameName) {
    addSummaryMetric(summaryMetricFamily, entry.getKey(), entry.getValue().getSnapshot(), 1.0D, entry.getValue().getCount());
  }
  return summaryMetricFamily;
}

/** @return an abbreviated summary of {@code hist}. */
public static String getShortHistogramReport(final Histogram hist) {
 Snapshot sn = hist.getSnapshot();
 return "mean=" + DOUBLE_FORMAT.format(sn.getMean()) +
   ", min=" + DOUBLE_FORMAT.format(sn.getMin()) +
   ", max=" + DOUBLE_FORMAT.format(sn.getMax()) +
   ", stdDev=" + DOUBLE_FORMAT.format(sn.getStdDev()) +
   ", 95th=" + DOUBLE_FORMAT.format(sn.get95thPercentile()) +
   ", 99th=" + DOUBLE_FORMAT.format(sn.get99thPercentile());
}

private void reportHistogram(List<Point> points, String prefix, String name, Histogram histogram, long timestamp)
  throws IOException {
 reportCounter(points, prefix, name, histogram, timestamp);
 reportSnapshot(points, prefix, name, histogram.getSnapshot(), timestamp, false);
}

private void reportHistogram(String name, Histogram histogram) {
 final Metric metric = createMetric(name, "histogram");
 reportHistogram(metric, histogram.getSnapshot());
}

private void reportHistogram(String prefix, String name, Histogram histogram, long timestamp) throws IOException {
 reportCounter(prefix, name, histogram, timestamp);
 reportSnapshot(prefix, name, histogram.getSnapshot(), timestamp, false);
}

  @TearDown(Level.Iteration)
  public void tearDown(Blackhole hole) {
    hole.consume(histogram.getSnapshot().getMedian());
    hole.consume(histogramSlidingTimeWindow.getSnapshot().getMedian());
    hole.consume(histogramUniform.getSnapshot().getMedian());
  }
}

private void reportHistograms(Map<MetricName, Histogram> histograms, long timestamp) {
  for (Map.Entry<MetricName, Histogram> entry : histograms.entrySet()) {
    final Histogram hist = entry.getValue();
    final Snapshot snapshot = hist.getSnapshot();
    reportLine(getInfluxDbLineProtocolString(entry.getKey()),
        "count=" + getIntegerValue(hist.getCount()) + ","
            + reportHistogramSnapshot(snapshot), timestamp);
  }
}

/** @return a summary of {@code hist}. */
public static String getHistogramReport(final Histogram hist) {
 Snapshot sn = hist.getSnapshot();
 return "mean=" + DOUBLE_FORMAT.format(sn.getMean()) +
   ", min=" + DOUBLE_FORMAT.format(sn.getMin()) +
   ", max=" + DOUBLE_FORMAT.format(sn.getMax()) +
   ", stdDev=" + DOUBLE_FORMAT.format(sn.getStdDev()) +
   ", 50th=" + DOUBLE_FORMAT.format(sn.getMedian()) +
   ", 75th=" + DOUBLE_FORMAT.format(sn.get75thPercentile()) +
   ", 95th=" + DOUBLE_FORMAT.format(sn.get95thPercentile()) +
   ", 99th=" + DOUBLE_FORMAT.format(sn.get99thPercentile()) +
   ", 99.9th=" + DOUBLE_FORMAT.format(sn.get999thPercentile()) +
   ", 99.99th=" + DOUBLE_FORMAT.format(sn.getValue(0.9999)) +
   ", 99.999th=" + DOUBLE_FORMAT.format(sn.getValue(0.99999));
}

 @Override
 double apply(Histogram hist) {
  return hist.getSnapshot().getValue(0.9999);
 }
};

 @Override
 double apply(Histogram hist) {
  return hist.getSnapshot().getStdDev();
 }
},

public static Histogram histogram(long count, Snapshot snapshot) {
  final Histogram histogram = mock(Histogram.class);
  when(histogram.getCount()).thenReturn(count);
  when(histogram.getSnapshot()).thenReturn(snapshot);
  return histogram;
}

public static Histogram metricSnapshot2Histogram(MetricSnapshot snapshot) {
  Histogram histogram;
  if (metricAccurateCal) {
    histogram = new Histogram(new ExponentiallyDecayingReservoir());
    byte[] points = snapshot.get_points();
    int len = snapshot.get_pointSize();
    updateHistogramPoints(histogram, points, len);
  } else {
    histogram = new Histogram(new JAverageReservoir());
    JAverageSnapshot averageSnapshot = (JAverageSnapshot) histogram.getSnapshot();
    averageSnapshot.setMetricSnapshot(snapshot.deepCopy());
  }
  return histogram;
}