Encapsulate common logic for MutableQuantile constructor

Author: Ravindra Dingankar

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/lib/MutableInverseQuantiles.java

@@ -69,41 +69,35 @@ static class InversePercentile extends Quantile {
    * @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 intervalSecs rollover interval (in seconds) of the estimator
+   * @param intervalSecs  rollover interval (in seconds) of the estimator
    */
   public MutableInverseQuantiles(String name, String description, String sampleName,
       String valueName, int intervalSecs) {
-    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);
+    super(name, description, sampleName, valueName, intervalSecs);
+  }
 
-    setNumInfo(info(ucName + "Num" + usName, String.format(
-        "Number of %s for %s with %ds interval", lsName, desc, intervalSecs)));
-    // Construct the MetricsInfos for the inverse quantiles, converting to inverse percentiles
+  /**
+   * Sets quantileInfo, estimator and schedules inverse quantiles for given interval.
+   *
+   * @param ucName capitalized name of the metric
+   * @param uvName capitalized type of the values
+   * @param desc uncapitalized long-form textual description of the metric
+   * @param lvName uncapitalized type of the values
+   * @param df Number formatter for inverse percentile value
+   */
+  void setQuantiles(String ucName, String uvName, String desc, String lvName, DecimalFormat df) {
+    // Construct the MetricsInfos for inverse quantiles, converting to inverse percentiles
     setQuantileInfos(INVERSE_QUANTILES.length);
-    DecimalFormat df = new DecimalFormat("###.####");
-    String nameTemplate = "thInversePercentile" + uvName;
-    String descTemplate = " inverse percentile " + lvName + " with " + intervalSecs
-        + " second interval for " + desc;
     for (int i = 0; i < INVERSE_QUANTILES.length; i++) {
-      double inversePercentile = 100 * (1 - INVERSE_QUANTILES[i].quantile);
-      addQuantileInfo(i, info(ucName + df.format(inversePercentile) + nameTemplate,
-          df.format(inversePercentile) + descTemplate));
+      double inversePercentile = 100 * INVERSE_QUANTILES[i].quantile;
+      String nameTemplate = ucName + df.format(inversePercentile) + "thInversePercentile" + uvName;
+      String descTemplate = df.format(inversePercentile) + " inverse percentile " + lvName
+          + " with " + getInterval() + " second interval for " + desc;
+      addQuantileInfo(i, info(nameTemplate, descTemplate));
     }
 
     setEstimator(new SampleQuantiles(INVERSE_QUANTILES));
-    setInterval(intervalSecs);
     scheduledTask = SCHEDULAR.scheduleWithFixedDelay(new RolloverSample(this),
-        intervalSecs, intervalSecs, TimeUnit.SECONDS);
-  }
-
-  public void stop() {
-    if (scheduledTask != null) {
-      scheduledTask.cancel(false);
-      scheduledTask = null;
+        getInterval(), getInterval(), TimeUnit.SECONDS);
     }
-  }
 }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/lib/MutableQuantiles.java

@@ -56,6 +56,7 @@ public class MutableQuantiles extends MutableMetric {
   private MetricsInfo numInfo;
   private MetricsInfo[] quantileInfos;
   private int intervalSecs;
+  private static DecimalFormat df = new DecimalFormat("###.####");
 
   private QuantileEstimator estimator;
   private long previousCount = 0;
@@ -91,26 +92,36 @@ public MutableQuantiles(String name, String description, String sampleName,
     String desc = StringUtils.uncapitalize(description);
     String lsName = StringUtils.uncapitalize(sampleName);
     String lvName = StringUtils.uncapitalize(valueName);
-    DecimalFormat df = new DecimalFormat("###.####");
-
+    
+    setInterval(interval);
     setNumInfo(info(ucName + "Num" + usName, String.format(
         "Number of %s for %s with %ds interval", lsName, desc, interval)));
+    setQuantiles(ucName, uvName, desc, lvName, df);
+  }
+
+  /**
+   * Sets quantileInfo, estimator and schedules quantiles for given interval.
+   * 
+   * @param ucName capitalized name of the metric
+   * @param uvName capitalized type of the values
+   * @param desc uncapitalized long-form textual description of the metric
+   * @param lvName uncapitalized type of the values
+   * @param df Number formatter for percentile value
+   */
+  void setQuantiles(String ucName, String uvName, String desc, String lvName, DecimalFormat df) {
     // Construct the MetricsInfos for the quantiles, converting to percentiles
     setQuantileInfos(quantiles.length);
-    String nameTemplate = "thPercentile" + uvName;
-    String descTemplate = " percentile " + lvName + " with " + interval
-        + " second interval for " + desc;
     for (int i = 0; i < quantiles.length; i++) {
       double percentile = 100 * quantiles[i].quantile;
-      addQuantileInfo(i, info(ucName + df.format(percentile) + nameTemplate,
-          df.format(percentile) + descTemplate));
+      String nameTemplate = ucName + df.format(percentile) + "thPercentile" + uvName;
+      String descTemplate = df.format(percentile) + " percentile " + lvName + " with " + getInterval()
+          + " second interval for " + desc;
+      addQuantileInfo(i, info(nameTemplate, descTemplate));
     }
 
     setEstimator(new SampleQuantiles(quantiles));
-
-    setInterval(interval);
     scheduledTask = scheduler.scheduleWithFixedDelay(new RolloverSample(this),
-        interval, interval, TimeUnit.SECONDS);
+        getInterval(), getInterval(), TimeUnit.SECONDS);
   }
 
   public MutableQuantiles() {}