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//
// UniqueExpireCache.h
//
// Library: Foundation
// Package: Cache
// Module: UniqueExpireCache
//
// Definition of the UniqueExpireCache class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_UniqueExpireCache_INCLUDED
#define Foundation_UniqueExpireCache_INCLUDED
#include "Poco/AbstractCache.h"
#include "Poco/UniqueExpireStrategy.h"
namespace Poco {
template <
class TKey,
class TValue,
class TMutex = FastMutex,
class TEventMutex = FastMutex
>
class UniqueExpireCache: public AbstractCache<TKey, TValue, UniqueExpireStrategy<TKey, TValue>, TMutex, TEventMutex>
/// An UniqueExpireCache caches entries for a given time amount. In contrast
/// to ExpireCache which only allows to set a per cache expiration value, it allows to define
/// expiration per CacheEntry.
/// Each TValue object must thus offer the following method:
///
/// const Poco::Timestamp& getExpiration() const;
///
/// which returns the absolute timepoint when the entry will be invalidated.
/// Accessing an object will NOT update this absolute expire timepoint.
/// You can use the Poco::ExpirationDecorator to add the getExpiration
/// method to values that do not have a getExpiration function.
///
/// Be careful when using an UniqueExpireCache. A cache is often used
/// like cache.has(x) followed by cache.get x). Note that it could happen
/// that the "has" call works, then the current execution thread gets descheduled, time passes,
/// the entry gets invalid, thus leading to an empty SharedPtr being returned
/// when "get" is invoked.
{
public:
UniqueExpireCache():
AbstractCache<TKey, TValue, UniqueExpireStrategy<TKey, TValue>, TMutex, TEventMutex>(UniqueExpireStrategy<TKey, TValue>())
{
}
~UniqueExpireCache()
{
}
private:
UniqueExpireCache(const UniqueExpireCache& aCache);
UniqueExpireCache& operator = (const UniqueExpireCache& aCache);
};
} // namespace Poco
#endif // Foundation_UniqueExpireCache_INCLUDED
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