Add Javadoc for HystrixMetrics

hystrix-core/src/main/java/com/netflix/hystrix/HystrixMetrics.java

@@ -19,14 +19,16 @@
 
 /**
  * Abstract base class for Hystrix metrics
+ *
+ * Read methods are public, as they may get called by arbitrary metrics consumers in other projects
+ * Write methods are protected, so that only internals may trigger them.
  */
 public abstract class HystrixMetrics {
 
     /**
      * Get the cumulative count since the start of the application for the given {@link HystrixRollingNumberEvent}.
      * 
-     * @param event
-     *            {@link HystrixRollingNumberEvent} of the event to retrieve a sum for
+     * @param event {@link HystrixRollingNumberEvent} of the event to retrieve a sum for
      * @return long cumulative count
      */
     public abstract long getCumulativeCount(HystrixRollingNumberEvent event);
@@ -36,17 +38,42 @@ public abstract class HystrixMetrics {
      * <p>
      * The rolling window is defined by {@link HystrixCommandProperties#metricsRollingStatisticalWindowInMilliseconds()}.
      * 
-     * @param event
-     *            {@link HystrixRollingNumberEvent} of the event to retrieve a sum for
+     * @param event {@link HystrixRollingNumberEvent} of the event to retrieve a sum for
      * @return long rolling count
      */
     public abstract long getRollingCount(HystrixRollingNumberEvent event);
 
+    /**
+     * Get the rolling max for the given {@link HystrixRollingNumberEvent}. This number is the high-water mark
+     * that the metric has observed in the rolling window.
+     * <p>
+     * The rolling window is defined by {@link HystrixCommandProperties#metricsRollingStatisticalWindowInMilliseconds()}.
+     *
+     * @param event {@link HystrixRollingNumberEvent} of the event to retrieve a rolling max for
+     * @return long rolling max
+     */
+    public abstract long getRollingMax(HystrixRollingNumberEvent event);
+
+    /**
+     * Increment the count of an {@link HystrixRollingNumberEvent}.
+     *
+     * @param event event type to increment
+     */
     protected abstract void addEvent(HystrixRollingNumberEvent event);
 
+    /**
+     * Add a count of {@link HystrixRollingNumberEvent}s
+     *
+     * @param event event type to add to
+     * @param value count to add
+     */
     protected abstract void addEventWithValue(HystrixRollingNumberEvent event, long value);
 
+    /**
+     * Set the observed value of a {@link HystrixRollingNumberEvent} into a counter that keeps track of maximum values
+     *
+     * @param event event type to observe count of
+     * @param value count observed
+     */
     protected abstract void updateRollingMax(HystrixRollingNumberEvent event, long value);
-
-    protected abstract long getRollingMax(HystrixRollingNumberEvent event);
 }