Ehcache Statistics by key

I am interested in getting statistics on the Ehcache I have running.

I would like to see the number of hits/misses for a given key over a period of time. Perhaps in the form of a map. For example.

For the passed hour (or however long it has been running)

Key A had 30 hits and 2 misses

Key B had 400 hits and 100 misses

Key C had 2 hits and 1 misses

Key D had 150 h开发者_运维知识库its and 10 misses

I have looked through the documentation (SampledCacheStatistics, SampledCacheStatisticsImpl, SampledCacheStatisticsWrapper, etc) and I am having a terrible time figuring this out.

Has anyone else had experience implementing this?

Any help or ideas on this would be MUCH appreciated!

The EhCache Monitor gives you that type of information... http://ehcache.org/documentation/monitor.html

Programmatic access is available as follows:

    CacheManager cacheManager = CacheManager.getInstance();
    String[] cacheNames = cacheManager.getCacheNames();
    for (int i = 0; i < cacheNames.length; i++) {
        String cacheName = cacheNames[i];
        System.out.println(cacheName+" - "+ cacheManager.getCache(cacheName).getStatistics().toString());
    }

You can't track misses on a per-key basis because the statistics are stored on object IN the cache and if there was a miss, there would be no element in the cache to track it. But if you want a hit-count for all the keys in a cache you'd need to do something like:

public Map<Object,long> getKeyHits(Ehcache cache)
{
  Map<Object,long> hitMap = new HashMap<Object,long>();
  Map<Object,Element> allElements = cache.getAll(cache.getKeys());
  for (Object key : allElements.keySet())
  {
    hitMap.put(key, allElements.get(key).hitCount());
  }
  return hitMap;
}

If you'd rather see statistics aggregated over an entire cache (or you want to track misses), you can call getStatistics() on the cache. See http://ehcache.org/apidocs/net/sf/ehcache/Ehcache.html.