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Added UniqueAccess caches

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This commit is contained in:
Peter Schojer 2007-10-29 14:36:40 +00:00
parent 9381a34928
commit 4d71a6e1d5
6 changed files with 357 additions and 68 deletions
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105
Foundation/include/Poco/AccessExpirationDecorator.h Normal file
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@ -0,0 +1,105 @@
//
// AccessExpirationDecorator.h
//
// $Id: //poco/Main/Foundation/include/Poco/AccessExpirationDecorator.h#1 $
//
// Library: Foundation
// Package: Events
// Module: AccessExpirationDecorator
//
// Implementation of the AccessExpirationDecorator template.
//
// 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
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
#ifndef Foundation_AccessExpirationDecorator_INCLUDED
#define Foundation_AccessExpirationDecorator_INCLUDED
#include "Poco/Timestamp.h"
#include "Poco/Timespan.h"
namespace Poco {
template <typename TArgs>
class AccessExpirationDecorator
/// AccessExpirationDecorator adds an expiration method to values so that they can be used
/// with the UniqueAccessExpireCache
{
public:
AccessExpirationDecorator():
_value(),
_expiresAt()
{
}
AccessExpirationDecorator(const TArgs& p, const Poco::Timespan::TimeDiff& diffInMs):
/// Creates an element that will expire in diff milliseconds
_value(p),
_expiresAt(diffInMs*1000)
{
}
AccessExpirationDecorator(const TArgs& p, const Poco::Timespan& timeSpan):
/// Creates an element that will expire after the given timeSpan
_value(p),
_expiresAt(timeSpan)
{
}
~AccessExpirationDecorator()
{
}
const Poco::Timespan& getExpiration() const
{
return _expiresAt;
}
const TArgs& value() const
{
return _value;
}
TArgs& value()
{
return _value;
}
private:
TArgs _value;
Timespan _expiresAt;
};
} // namespace Poco
#endif

58
Foundation/include/Poco/UniqueAccessExpireCache.h
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@ -39,31 +39,51 @@
#ifndef Foundation_UniqueAccessExpireCache_INCLUDED
#define Foundation_UniqueAccessExpireCache_INCLUDED
#include "Poco/AbstractCache.h"
#include "Poco/UniqueExpireCache.h"
#include "Poco/UniqueAccessExpireStrategy.h"
namespace Poco
{
template <class TKey, class TValue>
class UniqueAccessExpireCache: public Poco::AbstractCache<TKey, TValue, Poco::UniqueAccessExpireStrategy<TKey, TValue> >
namespace Poco {
template <class TKey, class TValue>
class UniqueAccessExpireCache: public AbstractCache<TKey, TValue, UniqueAccessExpireStrategy<TKey, TValue> >
/// An UniqueAccessExpireCache caches entries for a given time span. 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::Timespan& getExpiration() 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() + getExpiration().
/// 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.
///
/// Be careful when using an UniqueAccessExpireCache. 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:
UniqueAccessExpireCache():
AbstractCache<TKey, TValue, UniqueAccessExpireStrategy<TKey, TValue> >(UniqueAccessExpireStrategy<TKey, TValue>())
{
friend class Poco::UniqueAccessExpireStrategy<TKey, TValue>;
public:
UniqueAccessExpireCache ():
Poco::AbstractCache<TKey, TValue, Poco::UniqueAccessExpireStrategy<TKey, TValue> > (UniqueAccessExpireStrategy<TKey, TValue> (this))
{
}
}
~UniqueAccessExpireCache()
{
}
private:
UniqueAccessExpireCache(const UniqueAccessExpireCache& aCache);
UniqueAccessExpireCache& operator = (const UniqueAccessExpireCache& aCache);
};
~UniqueAccessExpireCache ()
{
}
private:
UniqueAccessExpireCache (const Poco::UniqueExpireCache<TKey, TValue>& aCache);
UniqueAccessExpireCache& operator = (const Poco::UniqueExpireCache<TKey, TValue>& aCache);
};
} // namespace Poco
#endif

91
Foundation/include/Poco/UniqueAccessExpireLRUCache.h Normal file
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@ -0,0 +1,91 @@
//
// UniqueAccessExpireLRUCache.h
//
// $Id: //poco/Main/Foundation/include/Poco/UniqueAccessExpireLRUCache.h#1 $
//
// 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
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// 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& getExpiration() 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() + getExpiration().
/// 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

159
Foundation/include/Poco/UniqueAccessExpireStrategy.h
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@ -44,66 +44,133 @@
#include "Poco/AbstractStrategy.h"
#include "Poco/Bugcheck.h"
#include "Poco/Timestamp.h"
#include "Poco/Timespan.h"
#include "Poco/EventArgs.h"
#include "Poco/UniqueExpireStrategy.h"
#include <set>
#include <map>
#include <stdio.h>
namespace Poco
namespace Poco {
template <
class TKey,
class TValue
>
class UniqueAccessExpireStrategy: public AbstractStrategy<TKey, TValue>
/// An UniqueExpireStrategy implements time based expiration of cache entries. In contrast
/// to ExpireStrategy 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.
{
template <class TKey, class TValue>
class UniqueAccessExpireCache;
template <class TKey, class TValue>
class UniqueAccessExpireStrategy : public Poco::UniqueExpireStrategy <TKey, TValue>
public:
typedef std::pair<TKey, Timespan> KeyExpire;
typedef std::multimap<Timestamp, KeyExpire> TimeIndex;
typedef typename TimeIndex::iterator IndexIterator;
typedef typename TimeIndex::const_iterator ConstIndexIterator;
typedef std::map<TKey, IndexIterator> Keys;
typedef typename Keys::iterator Iterator;
public:
UniqueAccessExpireStrategy()
/// Create an unique expire strategy.
{
public:
typedef std::map<TKey, SharedPtr<TValue > > DataHolder;
typedef typename DataHolder::iterator DataIterator;
}
typedef std::multimap<Poco::Timestamp, TKey> TimeIndex;
typedef typename TimeIndex::iterator IndexIterator;
typedef typename TimeIndex::const_iterator ConstIndexIterator;
typedef std::map<TKey, IndexIterator> Keys;
typedef typename Keys::iterator Iterator;
~UniqueAccessExpireStrategy()
{
}
UniqueAccessExpireStrategy (const Poco::UniqueAccessExpireCache<TKey, TValue>* cache)
: _cache (cache)
void onAdd(const void*, const KeyValueArgs <TKey, TValue>& args)
{
// the expire value defines how many millisecs in the future the
// value will expire, even insert negative values!
Timestamp expire;
expire += args.value().getExpiration().totalMicroseconds();
IndexIterator it = _keyIndex.insert(std::make_pair(expire, std::make_pair(args.key(), args.value().getExpiration())));
std::pair<Iterator, bool> stat = _keys.insert(std::make_pair(args.key(), it));
if (!stat.second)
{
_keyIndex.erase(stat.first->second);
stat.first->second = it;
}
}
void onRemove(const void*, const TKey& key)
{
Iterator it = _keys.find(key);
if (it != _keys.end())
{
_keyIndex.erase(it->second);
_keys.erase(it);
}
}
void onGet(const void*, const TKey& key)
{
// get updates the expiration time stamp
Iterator it = _keys.find(key);
if (it != _keys.end())
{
KeyExpire ke = it->second->second;
// gen new absolute expire value
Timestamp expire;
expire += ke.second.totalMicroseconds();
// delete old index
_keyIndex.erase(it->second);
IndexIterator itt = _keyIndex.insert(std::make_pair(expire, ke));
// update iterator
it->second = itt;
}
}
void onClear(const void*, const EventArgs& args)
{
_keys.clear();
_keyIndex.clear();
}
void onIsValid(const void*, ValidArgs<TKey>& args)
{
Iterator it = _keys.find(args.key());
if (it != _keys.end())
{
Timestamp now;
if (it->second->first <= now)
{
args.invalidate();
}
virtual void onAdd(const void*, const KeyValueArgs <TKey, TValue>& args)
{
const Timestamp& expire = args.value().getExpiration();
Timestamp now;
IndexIterator it = this->_keyIndex.insert(std::make_pair(now + (expire.epochMicroseconds () * 1000), args.key()));
std::pair<Iterator, bool> stat = this->_keys.insert(std::make_pair(args.key(), it));
if (!stat.second)
{
this->_keyIndex.erase(stat.first->second);
stat.first->second = it;
}
}
}
}
void onReplace(const void*, std::set<TKey>& elemsToRemove)
{
// Note: replace only informs the cache which elements
// it would like to remove!
// it does not remove them on its own!
IndexIterator it = _keyIndex.begin();
Timestamp now;
while (it != _keyIndex.end() && it->first < now)
{
elemsToRemove.insert(it->second.first);
++it;
}
}
protected:
Keys _keys; /// For faster replacement of keys, the iterator points to the _keyIndex map
TimeIndex _keyIndex; /// Maps time to key value
};
virtual void onGet (const void*, const TKey& key)
{
Iterator it = this->_keys.find (key);
if (it != this->_keys.end ()) {
DataIterator itd = _cache->_data.find (key);
if (itd != _cache->_data.end ()) {
this->_keyIndex.erase(it->second);
const Timestamp& expire = itd->second->getExpiration ();
Poco::Timestamp now;
IndexIterator itIdx = this->_keyIndex.insert (typename TimeIndex::value_type (now + (expire.epochMicroseconds () * 1000), key));
it->second = itIdx;
}
}
}
protected:
const Poco::UniqueAccessExpireCache<TKey, TValue>* _cache;
};
} // namespace Poco
#endif

5
Foundation/include/Poco/UniqueExpireCache.h
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@ -1,7 +1,7 @@
//
// UniqueExpireCache.h
//
// $Id: //poco/Main/Foundation/include/Poco/UniqueExpireCache.h#2 $
// $Id: //poco/Main/Foundation/include/Poco/UniqueExpireCache.h#3 $
//
// Library: Foundation
// Package: Cache
@ -57,6 +57,9 @@ class UniqueExpireCache: public AbstractCache<TKey, TValue, UniqueExpireStrategy
/// 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

7
Foundation/include/Poco/UniqueExpireLRUCache.h
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@ -1,7 +1,7 @@
//
// UniqueExpireLRUCache.h
//
// $Id: //poco/Main/Foundation/include/Poco/UniqueExpireLRUCache.h#2 $
// $Id: //poco/Main/Foundation/include/Poco/UniqueExpireLRUCache.h#3 $
//
// Library: Foundation
// Package: Cache
@ -55,13 +55,16 @@ template <
>
class UniqueExpireLRUCache: public AbstractCache<TKey, TValue, StrategyCollection<TKey, TValue> >
/// A UniqueExpireLRUCache combines LRU caching and time based per entry expire caching.
/// Once can define for each cache entry a seperate timepoint
/// 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::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.
{
public:
UniqueExpireLRUCache(long cacheSize = 1024):