Returns statistics for this cache.
Returns whether a value associated with the specified key exists in the cache.
Returns statistics for the specified entry.
Retrieves the value associated with the specified key if it exists.
Retrieves the value associated with the specified key if it exists. Otherwise computes the value with the lookup function, puts it in the cache, and returns it.
Invalidates the value associated with the specified key.
Invalidates all values in the cache.
Computes the value associated with the specified key, with the lookup function, and puts it in the cache.
Computes the value associated with the specified key, with the lookup
function, and puts it in the cache. The difference between this and
get
method is that refresh
triggers (re)computation of the value
without invalidating it in the cache, so any request to the associated
key can still be served while the value is being re-computed/retrieved
by the lookup function. Additionally, refresh
always triggers the
lookup function, disregarding the last Error
.
Returns the approximate number of values in the cache.
A
Cache
is defined in terms of a lookup function that, given a key of typeKey
, can either fail with an error of typeError
or succeed with a value of typeValue
. Getting a value from the cache will either return the previous result of the lookup function if it is available or else compute a new result with the lookup function, put it in the cache, and return it.A cache also has a specified capacity and time to live. When the cache is at capacity the least recently accessed values in the cache will be removed to make room for new values. Getting a value with a life older than the specified time to live will result in a new value being computed with the lookup function and returned when available.
The cache is safe for concurrent access. If multiple fibers attempt to get the same key the lookup function will only be computed once and the result will be returned to all fibers.