@GwtCompatible public final class CacheStats extends Object
Cache
. Instances of this class are immutable.
Cache statistics are incremented according to the following rules:
hitCount
is incremented.
missCount
and loadSuccessCount
are
incremented, and the total loading time, in nanoseconds, is added to totalLoadTime
.
missCount
and loadExceptionCount
are incremented, and the total loading time, in nanoseconds, is added to
totalLoadTime
.
missCount
.
evictionCount
is incremented.
A lookup is specifically defined as an invocation of one of the methods
LoadingCache.get(Object)
, LoadingCache.getUnchecked(Object)
,
Cache.get(Object, Callable)
, or LoadingCache.getAll(Iterable)
.
Constructor and Description |
---|
CacheStats(long hitCount,
long missCount,
long loadSuccessCount,
long loadExceptionCount,
long totalLoadTime,
long evictionCount)
Constructs a new
CacheStats instance. |
Modifier and Type | Method and Description |
---|---|
double |
averageLoadPenalty()
Returns the average time spent loading new values.
|
boolean |
equals(Object object) |
long |
evictionCount()
Returns the number of times an entry has been evicted.
|
int |
hashCode() |
long |
hitCount()
Returns the number of times
Cache lookup methods have returned a cached value. |
double |
hitRate()
Returns the ratio of cache requests which were hits.
|
long |
loadCount()
Returns the total number of times that
Cache lookup methods attempted to load new
values. |
long |
loadExceptionCount()
Returns the number of times
Cache lookup methods threw an exception while loading a new
value. |
double |
loadExceptionRate()
Returns the ratio of cache loading attempts which threw exceptions.
|
long |
loadSuccessCount()
Returns the number of times
Cache lookup methods have successfully loaded a new value. |
CacheStats |
minus(CacheStats other)
Returns a new
CacheStats representing the difference between this CacheStats
and other . |
long |
missCount()
Returns the number of times
Cache lookup methods have returned an uncached (newly
loaded) value, or null. |
double |
missRate()
Returns the ratio of cache requests which were misses.
|
CacheStats |
plus(CacheStats other)
Returns a new
CacheStats representing the sum of this CacheStats and
other . |
long |
requestCount()
Returns the number of times
Cache lookup methods have returned either a cached or
uncached value. |
String |
toString() |
long |
totalLoadTime()
Returns the total number of nanoseconds the cache has spent loading new values.
|
public CacheStats(long hitCount, long missCount, long loadSuccessCount, long loadExceptionCount, long totalLoadTime, long evictionCount)
CacheStats
instance.
Five parameters of the same type in a row is a bad thing, but this class is not constructed by end users and is too fine-grained for a builder.
public long requestCount()
Cache
lookup methods have returned either a cached or
uncached value. This is defined as hitCount + missCount
.public long hitCount()
Cache
lookup methods have returned a cached value.public double hitRate()
hitCount / requestCount
, or 1.0
when requestCount == 0
. Note that
hitRate + missRate =~ 1.0
.public long missCount()
public double missRate()
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.public long loadCount()
Cache
lookup methods attempted to load new
values. This includes both successful load operations, as well as those that threw exceptions.
This is defined as loadSuccessCount + loadExceptionCount
.public long loadSuccessCount()
Cache
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
.public long loadExceptionCount()
Cache
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
.public double loadExceptionRate()
loadExceptionCount / (loadSuccessCount + loadExceptionCount)
, or 0.0
when
loadSuccessCount + loadExceptionCount == 0
.public long totalLoadTime()
loadSuccessCount
or loadExceptionCount
is incremented.public double averageLoadPenalty()
totalLoadTime / (loadSuccessCount + loadExceptionCount)
.public long evictionCount()
public CacheStats minus(CacheStats other)
CacheStats
representing the difference between this CacheStats
and other
. Negative values, which aren't supported by CacheStats
will be
rounded up to zero.public CacheStats plus(CacheStats other)
CacheStats
representing the sum of this CacheStats
and
other
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