ClickHouse/contrib/libpoco/Foundation/include/Poco/ExpireCache.h

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//
// ExpireCache.h
//
// $Id: //poco/1.4/Foundation/include/Poco/ExpireCache.h#1 $
//
// Library: Foundation
// Package: Cache
// Module: ExpireCache
//
// Definition of the ExpireCache class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_ExpireCache_INCLUDED
#define Foundation_ExpireCache_INCLUDED
#include "Poco/AbstractCache.h"
#include "Poco/ExpireStrategy.h"
namespace Poco {
template <
class TKey,
class TValue,
class TMutex = FastMutex,
class TEventMutex = FastMutex
>
class ExpireCache: public AbstractCache<TKey, TValue, ExpireStrategy<TKey, TValue>, TMutex, TEventMutex>
/// An ExpireCache caches entries for a fixed time period (per default 10 minutes).
/// Entries expire independently of the access pattern, i.e. after a constant time.
/// If you require your objects to expire after they were not accessed for a given time
/// period use a Poco::AccessExpireCache.
///
/// Be careful when using an ExpireCache. 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:
ExpireCache(Timestamp::TimeDiff expire = 600000):
AbstractCache<TKey, TValue, ExpireStrategy<TKey, TValue>, TMutex, TEventMutex>(ExpireStrategy<TKey, TValue>(expire))
{
}
~ExpireCache()
{
}
private:
ExpireCache(const ExpireCache& aCache);
ExpireCache& operator = (const ExpireCache& aCache);
};
} // namespace Poco
#endif // Foundation_ExpireCache_INCLUDED