CacheStatistics (WSO2 Carbon - JSR 107 API 4.4.36 API)

All Known Subinterfaces:

CacheMXBean, CacheStatisticsMXBean

All Known Implementing Classes:

CacheMXBeanImpl, CacheStatisticsImpl
```
public interface CacheStatistics
```
Cache statistics.
Statistics are accumulated from the time a cache is created. They can be reset to zero using clear().
There are no defined consistency semantics for statistics. Refer to the implementation for precise semantics.

Since:

1.0

Author:

Greg Luck

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`clear()` Clears the statistics counters to 0 for the associated Cache.
`float`	`getAverageGetMillis()` The mean time to execute gets.
`float`	`getAveragePutMillis()` The mean time to execute puts.
`float`	`getAverageRemoveMillis()` 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 which 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.
`Date`	`getStartAccumulationDate()` The date from which statistics have been accumulated.

- Method Detail
  - clear
```
void clear()
```
    Clears the statistics counters to 0 for the associated Cache.
  - getStartAccumulationDate
```
Date getStartAccumulationDate()
```
    The date from which statistics have been accumulated. Because statistics can be cleared, this is not necessarily since the cache was started.
    
    Returns:
    the date statistics started being accumulated
  - getCacheHits
```
long getCacheHits()
```
    The number of get requests that were satisfied by the cache.
    In a caches with multiple tiered storage, a hit may be implemented as a hit to the cache or to the first tier.
    
    Returns:
    the number of hits
  - getCacheHitPercentage
```
float getCacheHitPercentage()
```
    This is a measure of cache efficiency.
    It is calculated as getCacheHits() divided by getCacheGets() * 100.
    
    Returns:
    the percentage of successful hits, as a decimal e.g 75.
  - getCacheMisses
```
long getCacheMisses()
```
    A miss is a get request which is not satisfied.
    In a simple cache a miss occurs when the cache does not satisfy the request.
    In a 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 which 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 a caches with multiple tiered storage, a gets 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 hits
  - 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 hits
  - 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 from the cache
  - getAverageGetMillis
```
float getAverageGetMillis()
```
    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 milliseconds
  - getAveragePutMillis
```
float getAveragePutMillis()
```
    The mean time to execute puts.
    
    Returns:
    the time in milliseconds
  - getAverageRemoveMillis
```
float getAverageRemoveMillis()
```
    The mean time to execute removes.
    
    Returns:
    the time in milliseconds

Interface CacheStatistics

Method Summary

Method Detail

clear

getStartAccumulationDate

getCacheHits

getCacheHitPercentage

getCacheMisses

getCacheMissPercentage

getCacheGets

getCachePuts

getCacheRemovals

getCacheEvictions

getAverageGetMillis

getAveragePutMillis

getAverageRemoveMillis