# Poco

# template < class TKey, class TValue, class TMutex = FastMutex, class TEventMutex = FastMutex >

# class UniqueAccessExpireLRUCache

Library: Foundation
Package: Cache
Header: Poco/UniqueAccessExpireLRUCache.h

## Description

A UniqueAccessExpireLRUCache combines LRU caching and time based per entry expire caching. One can define for each cache entry a separate timepoint but also limit the size of the cache (per default: 1024). Each TValue object must thus offer the following method:

    const Poco::Timespan& getTimeout() const;

which returns the relative timespan for how long the entry should be valid without being accessed! The absolute expire timepoint is calculated as now() + getTimeout(). Accessing an object will update this absolute expire timepoint. You can use the Poco::AccessExpirationDecorator to add the getExpiration method to values that do not have a getExpiration function.

## Inheritance

Direct Base Classes: AbstractCache < TKey, TValue, StrategyCollection < TKey, TValue >, TMutex, TEventMutex >

All Base Classes: AbstractCache < TKey, TValue, StrategyCollection < TKey, TValue >, TMutex, TEventMutex >

## Constructors

### UniqueAccessExpireLRUCache

UniqueAccessExpireLRUCache(
std::size_t cacheSize = 1024
);

## Destructor

### ~UniqueAccessExpireLRUCache

~UniqueAccessExpireLRUCache();