ExpiringCache

Data cache class template with element life time limitation. Stores items of raw data, either of fixed or dynamic size. When the life time of an item, which is the difference between its creation time and the current wall clock time, has expired, it is removed automatically on the next getRaw()/exists() access.

class ExpiringCache : Cache!(ValueSize, true), IExpiringCacheInfo (

size_t ValueSize = 0

) {

import ocean.core.Verify;;

time_t lifetime;

time_t empty_lifetime;

protected

uint n_expired;

this(size_t max_items, time_t lifetime, time_t empty_lifetime);

ValueRef getRaw(hash_t key);

ValueRef getRaw(hash_t key, bool expired);

ValueRef getOrCreateRaw(hash_t key, bool existed);

bool exists(hash_t key, bool expired);

bool exists(hash_t key);

uint num_expired();

void resetStats();

}

Constructors

this this(size_t max_items, time_t lifetime, time_t empty_lifetime): Constructor.

Members

Functions

exists bool exists(hash_t key, bool expired): Checks whether an item exists in the cache and updates its access time. If the life time of the item has expired, it is removed.
exists bool exists(hash_t key): Checks whether an item exists in the cache and updates its access time. If the life time of the item has expired, it is removed.
getOrCreateRaw ValueRef getOrCreateRaw(hash_t key, bool existed): Gets an item from the cache or creates it if not already existing. If the item was found in the cache, its access time is updated, otherwise its create time is set. If the item was found but was expired, the effect is the same as if the item was not found.
getRaw ValueRef getRaw(hash_t key): Gets an item from the cache. If the item was found in the cache, its access time is updated. If the item life time has expired, it is automatically removed.
getRaw ValueRef getRaw(hash_t key, bool expired): Gets an item from the cache. If the item was found in the cache, its access time is updated. If the item life time has expired, it is automatically removed.
num_expired uint num_expired()
resetStats void resetStats(): Resets the statistics counter values.

Variables

empty_lifetime time_t empty_lifetime;: Life time for empty items in seconds; may be changed at any time. This value must be at least 1. Can be same as lifetime.
lifetime time_t lifetime;: Life time for non-empty items in seconds; may be changed at any time. This value must be at least 1.
n_expired uint n_expired;: Counts the number of lookups where an existing element was expired.