Interface StatsCounter

All Known Implementing Classes:
ConcurrentStatsCounter, DisabledStatsCounter, GuardedStatsCounter

@ThreadSafe public interface StatsCounter
Accumulates statistics during the operation of a Cache for presentation by Cache.stats(). This is solely intended for consumption by Cache implementors.
  • Method Details

    • recordHits

      void recordHits(@Nonnegative int count)
      Records cache hits. This should be called when a cache request returns a cached value.
      Parameters:
      count - the number of hits to record
    • recordMisses

      void recordMisses(@Nonnegative int count)
      Records cache misses. This should be called when a cache request returns a value that was not found in the cache. This method should be called by the loading thread, as well as by threads blocking on the load. Multiple concurrent calls to Cache lookup methods with the same key on an absent value should result in a single call to either recordLoadSuccess or recordLoadFailure and multiple calls to this method, despite all being served by the results of a single load operation.
      Parameters:
      count - the number of misses to record
    • recordLoadSuccess

      void recordLoadSuccess(@Nonnegative long loadTime)
      Records the successful load of a new entry. This should be called when a cache request causes an entry to be loaded, and the loading completes successfully. In contrast to recordMisses(int), this method should only be called by the loading thread.
      Parameters:
      loadTime - the number of nanoseconds the cache spent computing or retrieving the new value
    • recordLoadFailure

      void recordLoadFailure(@Nonnegative long loadTime)
      Records the failed load of a new entry. This should be called when a cache request causes an entry to be loaded, but either no value is found or an exception is thrown while loading the entry. In contrast to recordMisses(int), this method should only be called by the loading thread.
      Parameters:
      loadTime - the number of nanoseconds the cache spent computing or retrieving the new value prior to discovering the value doesn't exist or an exception being thrown
    • recordEviction

      @Deprecated void recordEviction()
      Deprecated.
      Use recordEviction(int) instead. This method is scheduled for removal in version 3.0.0.
      Records the eviction of an entry from the cache. This should only been called when an entry is evicted due to the cache's eviction strategy, and not as a result of manual invalidations.
    • recordEviction

      default void recordEviction(int weight)
      Records the eviction of an entry from the cache. This should only been called when an entry is evicted due to the cache's eviction strategy, and not as a result of manual invalidations.
      Parameters:
      weight - the weight of the evicted entry
    • snapshot

      @Nonnull CacheStats snapshot()
      Returns a snapshot of this counter's values. Note that this may be an inconsistent view, as it may be interleaved with update operations.
      Returns:
      a snapshot of this counter's values
    • disabledStatsCounter

      @Nonnull static StatsCounter disabledStatsCounter()
      Returns an accumulator that does not record any cache events.
      Returns:
      an accumulator that does not record metrics
    • guardedStatsCounter

      @Nonnull static StatsCounter guardedStatsCounter(@Nonnull StatsCounter statsCounter)
      Returns an accumulator that suppresses and logs any exception thrown by the delegate statsCounter.
      Parameters:
      statsCounter - the accumulator to delegate to
      Returns:
      an accumulator that suppresses and logs any exception thrown by the delegate