Interface CacheStats

All Known Implementing Classes:
DefaultCacheStats

public interface CacheStats
  • Method Summary

    Modifier and Type
    Method
    Description
    double
    Returns the average time spent loading new values.
    long
    Returns the number of times an entry has been evicted.
    long
    Returns the number of times lookup methods have returned a cached value.
    double
    Returns the ratio of cache requests which were hits.
    long
    Returns the total number of times that lookup methods attempted to load new values.
    long
    Returns the number of times lookup methods threw an exception while loading a new value.
    double
    Returns the ratio of cache loading attempts which threw exceptions.
    long
    Returns the number of times lookup methods have successfully loaded a new value.
    Returns a new ICacheStats representing the difference between this ICacheStats and other.
    long
    Returns the number of times lookup methods have returned an uncached (newly loaded) value, or null.
    double
    Returns the ratio of cache requests which were misses.
    Returns a new ICacheStats representing the sum of this ICacheStats and other.
    long
    Returns the number of times lookup methods have returned either a cached or uncached value.
    long
    Returns the total number of nanoseconds the cache has spent loading new values.
  • Method Details

    • requestCount

      long requestCount()
      Returns the number of times lookup methods have returned either a cached or uncached value. This is defined as hitCount + missCount.

      Note: the values of the metrics are undefined in case of overflow (though it is guaranteed not to throw an exception). If you require specific handling, we recommend implementing your own stats collector.

    • hitCount

      long hitCount()
      Returns the number of times lookup methods have returned a cached value.
    • hitRate

      double hitRate()
      Returns the ratio of cache requests which were hits. This is defined as hitCount / requestCount, or 1.0 when requestCount == 0. Note that hitRate + missRate =~ 1.0.
    • missCount

      long missCount()
      Returns the number of times lookup methods have returned an uncached (newly loaded) value, or null. Multiple concurrent calls to lookup methods on an absent value can result in multiple misses, all returning the results of a single cache load operation.
    • missRate

      double missRate()
      Returns the ratio of cache requests which were misses. This is defined as missCount / requestCount, or 0.0 when requestCount == 0. Note that hitRate + missRate =~ 1.0. Cache misses include all requests which weren't cache hits, including requests which resulted in either successful or failed loading attempts, and requests which waited for other threads to finish loading. It is thus the case that missCount >= loadSuccessCount + loadExceptionCount. Multiple concurrent misses for the same key will result in a single load operation.
    • loadCount

      long loadCount()
      Returns the total number of times that lookup methods attempted to load new values. This includes both successful load operations and those that threw exceptions. This is defined as loadSuccessCount + loadExceptionCount.

      Note: the values of the metrics are undefined in case of overflow (though it is guaranteed not to throw an exception). If you require specific handling, we recommend implementing your own stats collector.

    • loadSuccessCount

      long loadSuccessCount()
      Returns the number of times lookup methods have successfully loaded a new value. This is usually incremented in conjunction with missCount(), though missCount is also incremented when an exception is encountered during cache loading (see loadExceptionCount()). Multiple concurrent misses for the same key will result in a single load operation. This may be incremented not in conjunction with missCount if the load occurs as a result of a refresh or if the cache loader returned more items than was requested. missCount may also be incremented not in conjunction with this (nor loadExceptionCount()) on calls to getIfPresent.
    • loadExceptionCount

      long loadExceptionCount()
      Returns the number of times lookup methods threw an exception while loading a new value. This is usually incremented in conjunction with missCount, though missCount is also incremented when cache loading completes successfully (see loadSuccessCount()). Multiple concurrent misses for the same key will result in a single load operation. This may be incremented not in conjunction with missCount if the load occurs as a result of a refresh or if the cache loader returned more items than was requested. missCount may also be incremented not in conjunction with this (nor loadSuccessCount()) on calls to getIfPresent.
    • loadExceptionRate

      double loadExceptionRate()
      Returns the ratio of cache loading attempts which threw exceptions. This is defined as loadExceptionCount / (loadSuccessCount + loadExceptionCount), or 0.0 when loadSuccessCount + loadExceptionCount == 0.

      Note: the values of the metrics are undefined in case of overflow (though it is guaranteed not to throw an exception). If you require specific handling, we recommend implementing your own stats collector.

    • totalLoadTime

      long totalLoadTime()
      Returns the total number of nanoseconds the cache has spent loading new values. This can be used to calculate the miss penalty. This value is increased every time loadSuccessCount or loadExceptionCount is incremented.
    • averageLoadPenalty

      double averageLoadPenalty()
      Returns the average time spent loading new values. This is defined as totalLoadTime / (loadSuccessCount + loadExceptionCount).

      Note: the values of the metrics are undefined in case of overflow (though it is guaranteed not to throw an exception). If you require specific handling, we recommend implementing your own stats collector.

    • evictionCount

      long evictionCount()
      Returns the number of times an entry has been evicted. This count does not include manual invalidations.
    • minus

      CacheStats minus(CacheStats other)
      Returns a new ICacheStats representing the difference between this ICacheStats and other. Negative values, which aren't supported by ICacheStats will be rounded up to zero.
    • plus

      CacheStats plus(CacheStats other)
      Returns a new ICacheStats representing the sum of this ICacheStats and other.

      Note: the values of the metrics are undefined in case of overflow (though it is guaranteed not to throw an exception). If you require specific handling, we recommend implementing your own stats collector.