topical media & game development
lib-of-vs-libs-Poco-include-Poco-UniqueAccessExpireLRUCache.h / h
//
// UniqueAccessExpireLRUCache.h
//
//
//
// Library: Foundation
// Package: Cache
// Module: UniqueAccessExpireLRUCache
//
// Definition of the UniqueAccessExpireLRUCache class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
ifndef Foundation_UniqueAccessExpireLRUCache_INCLUDED
define Foundation_UniqueAccessExpireLRUCache_INCLUDED
include "Poco/AbstractCache.h"
include "Poco/StrategyCollection.h"
include "Poco/UniqueAccessExpireStrategy.h"
include "Poco/LRUStrategy.h"
namespace Poco {
template <
class TKey,
class TValue
>
class UniqueAccessExpireLRUCache: public AbstractCache<TKey, TValue, StrategyCollection<TKey, TValue> >
A UniqueAccessExpireLRUCache combines LRU caching and time based per entry expire caching.
One can define for each cache entry a seperate 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.
{
public:
UniqueAccessExpireLRUCache(long cacheSize = 1024):
AbstractCache<TKey, TValue, StrategyCollection<TKey, TValue> >(StrategyCollection<TKey, TValue>())
{
this->_strategy.pushBack(new LRUStrategy<TKey, TValue>(cacheSize));
this->_strategy.pushBack(new UniqueAccessExpireStrategy<TKey, TValue>());
}
~UniqueAccessExpireLRUCache()
{
}
private:
UniqueAccessExpireLRUCache(const UniqueAccessExpireLRUCache& aCache);
UniqueAccessExpireLRUCache& operator = (const UniqueAccessExpireLRUCache& aCache);
};
} // namespace Poco
endif // Foundation_UniqueAccessExpireLRUCache_INCLUDED
(C) Æliens
04/09/2009
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