CacheStatistics (Hazelcast Root 3.4 API)

All Known Implementing Classes:

CacheStatisticsImpl
```
public interface CacheStatistics
```
Cache statistics
Cache statistics are accumulated since the time a cache is created.
An instance of this class represents local node values only! For an accumulated view on cluster level the user has to retrieve all nodes statistics and aggregate values on his own.

Sample code:
```
       ICache<Key, Value> unwrappedCache =  cache.unwrap( ICache.class );
       CacheStatistics cacheStatistics = unwrappedCache.getLocalCacheStatistics();
       long cacheHits = cacheStatistics.getCacheHits();
     
```
Since:

3.3.1

Method Summary

Methods
Modifier and Type	Method and Description
`float`	`getAverageGetTime()` The mean time to execute gets.
`float`	`getAveragePutTime()` The mean time to execute puts.
`float`	`getAverageRemoveTime()` The mean time to execute removes.
`long`	`getCacheEvictions()` The total number of evictions from the cache.
`long`	`getCacheGets()` The total number of requests to the cache.
`float`	`getCacheHitPercentage()` This is a measure of cache efficiency.
`long`	`getCacheHits()` The number of get requests that were satisfied by the cache.
`long`	`getCacheMisses()` A miss is a get request that is not satisfied.
`float`	`getCacheMissPercentage()` Returns the percentage of cache accesses that did not find a requested entry in the cache.
`long`	`getCachePuts()` The total number of puts to the cache.
`long`	`getCacheRemovals()` The total number of removals from the cache.

- Method Detail
  - getCacheHits
```
long getCacheHits()
```
    The number of get requests that were satisfied by the cache.
    Cache.containsKey(Object) is not a get request for statistics purposes.
    In caches with multiple tiered storage, a hit may be implemented as a hit to the cache or to the first tier.
    For an EntryProcessor, a hit occurs when the key exists and an entry processor can be invoked against it, even if no methods of Cache.Entry or MutableEntry are called.
    
    Returns:
    the number of hits
  - getCacheHitPercentage
```
float getCacheHitPercentage()
```
    This is a measure of cache efficiency.
    It is calculated as: getCacheHits() divided by () * 100.
    
    Returns:
    the percentage of successful hits, as a decimal, e.g 75
  - getCacheMisses
```
long getCacheMisses()
```
    A miss is a get request that is not satisfied.
    In a simple cache, a miss occurs when the cache does not satisfy the request.
    Cache.containsKey(Object) is not a get request for statistics purposes.
    For an EntryProcessor, a miss occurs when the key does not exist and therefore an entry processor cannot be invoked against it.
    In caches with multiple tiered storage, a miss may be implemented as a miss to the cache or to the first tier.
    In a read-through cache, a miss is an absence of the key in the cache that will trigger a call to a CacheLoader. So it is still a miss even though the cache will load and return the value.
    Refer to the implementation for precise semantics.
    
    Returns:
    the number of misses
  - getCacheMissPercentage
```
float getCacheMissPercentage()
```
    Returns the percentage of cache accesses that did not find a requested entry in the cache.
    This is calculated as getCacheMisses() divided by getCacheGets() * 100.
    
    Returns:
    the percentage of accesses that failed to find anything
  - getCacheGets
```
long getCacheGets()
```
    The total number of requests to the cache. This will be equal to the sum of the hits and misses.
    A "get" is an operation that returns the current or previous value. It does not include checking for the existence of a key.
    In caches with multiple tiered storage, a get may be implemented as a get to the cache or to the first tier.
    
    Returns:
    the number of gets
  - getCachePuts
```
long getCachePuts()
```
    The total number of puts to the cache.
    A put is counted even if it is immediately evicted.
    Replaces, where a put occurs which overrides an existing mapping is counted as a put.
    
    Returns:
    the number of puts
  - getCacheRemovals
```
long getCacheRemovals()
```
    The total number of removals from the cache. This does not include evictions, where the cache itself initiates the removal to make space.
    
    Returns:
    the number of removals
  - getCacheEvictions
```
long getCacheEvictions()
```
    The total number of evictions from the cache. An eviction is a removal initiated by the cache itself to free up space. An eviction is not treated as a removal and does not appear in the removal counts.
    
    Returns:
    the number of evictions
  - getAverageGetTime
```
float getAverageGetTime()
```
    The mean time to execute gets.
    In a read-through cache, the time taken to load an entry on miss is not included in get time.
    
    Returns:
    the time in µs
  - getAveragePutTime
```
float getAveragePutTime()
```
    The mean time to execute puts.
    
    Returns:
    the time in µs
  - getAverageRemoveTime
```
float getAverageRemoveTime()
```
    The mean time to execute removes.
    
    Returns:
    the time in µs

Interface CacheStatistics

Method Summary

Method Detail

getCacheHits

getCacheHitPercentage

getCacheMisses

getCacheMissPercentage

getCacheGets

getCachePuts

getCacheRemovals

getCacheEvictions

getAverageGetTime

getAveragePutTime

getAverageRemoveTime