new trunk (base for 1.5)

windows build only

Foundation/include/Poco/UniqueAccessExpireCache.h

@@ -0,0 +1,95 @@
+//
+// UniqueAccessExpireCache.h
+//
+// $Id: //poco/1.4/Foundation/include/Poco/UniqueAccessExpireCache.h#1 $
+//
+// Library: Foundation
+// Package: Cache
+// Module:  UniqueAccessExpireCache
+//
+// Definition of the UniqueAccessExpireCache 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_UniqueAccessExpireCache_INCLUDED
+#define Foundation_UniqueAccessExpireCache_INCLUDED
+
+
+#include "Poco/AbstractCache.h"
+#include "Poco/UniqueAccessExpireStrategy.h"
+
+
+namespace Poco {
+
+
+template <
+	class TKey, 
+	class TValue,
+	class TMutex = FastMutex, 
+	class TEventMutex = FastMutex
+> 
+class UniqueAccessExpireCache: public AbstractCache<TKey, TValue, UniqueAccessExpireStrategy<TKey, TValue>, TMutex, TEventMutex>
+	/// 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& 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.
+	///
+	/// 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>, TMutex, TEventMutex>(UniqueAccessExpireStrategy<TKey, TValue>())
+	{
+	}
+
+	~UniqueAccessExpireCache()
+	{
+	}
+
+private:
+	UniqueAccessExpireCache(const UniqueAccessExpireCache& aCache);
+	UniqueAccessExpireCache& operator = (const UniqueAccessExpireCache& aCache);
+};
+
+
+} // namespace Poco
+
+
+#endif // Foundation_UniqueAccessExpireCache_INCLUDED