import org.apache.hadoop.metrics2.util.SampleQuantiles; //导入依赖的package包/类
/**
 * Instantiates a new {@link MutableQuantiles} for a metric that rolls itself
 * over on the specified time interval.
 * 
 * @param name
 *          of the metric
 * @param description
 *          long-form textual description of the metric
 * @param sampleName
 *          type of items in the stream (e.g., "Ops")
 * @param valueName
 *          type of the values
 * @param interval
 *          rollover interval (in seconds) of the estimator
 */
public MutableQuantiles(String name, String description, String sampleName,
    String valueName, int interval) {
  String ucName = StringUtils.capitalize(name);
  String usName = StringUtils.capitalize(sampleName);
  String uvName = StringUtils.capitalize(valueName);
  String desc = StringUtils.uncapitalize(description);
  String lsName = StringUtils.uncapitalize(sampleName);
  String lvName = StringUtils.uncapitalize(valueName);

  numInfo = info(ucName + "Num" + usName, String.format(
      "Number of %s for %s with %ds interval", lsName, desc, interval));
  // Construct the MetricsInfos for the quantiles, converting to percentiles
  quantileInfos = new MetricsInfo[quantiles.length];
  String nameTemplate = ucName + "%dthPercentile" + uvName;
  String descTemplate = "%d percentile " + lvName + " with " + interval
      + " second interval for " + desc;
  for (int i = 0; i < quantiles.length; i++) {
    int percentile = (int) (100 * quantiles[i].quantile);
    quantileInfos[i] = info(String.format(nameTemplate, percentile),
        String.format(descTemplate, percentile));
  }

  estimator = new SampleQuantiles(quantiles);

  this.interval = interval;
  scheduler.scheduleAtFixedRate(new RolloverSample(this), interval, interval,
      TimeUnit.SECONDS);
}