Added cache classes

Foundation/include/Poco/AccessExpireCache.h

@@ -0,0 +1,80 @@
+//
+// AccessExpireCache.h
+//
+// $Id: //poco/Main/Foundation/include/Poco/AccessExpireCache.h#1 $
+//
+// Library: Foundation
+// Package: Cache
+// Module:  AccessExpireCache
+//
+// Definition of the AccessExpireCache 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_AccessExpireCache_INCLUDED
+#define  Foundation_AccessExpireCache_INCLUDED
+
+
+#include "Poco/AbstractCache.h"
+#include "Poco/AccessExpireStrategy.h"
+
+
+namespace Poco {
+
+
+template <class TKey, class TValue> 
+class AccessExpireCache: public AbstractCache<TKey, TValue, AccessExpireStrategy<TKey, TValue> >
+	/// An AccessExpireCache caches entries for a fixed time period (per default 10 minutes).
+	/// Entries expire when they are not accessed with get() during this time period. Each access resets
+	/// the start time for expiration.
+	/// Be careful when using an AccessExpireCache. 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:
+	AccessExpireCache(Timestamp::TimeDiff expire = 600000): 
+		AbstractCache<TKey, TValue, AccessExpireStrategy<TKey, TValue> >(AccessExpireStrategy<TKey, TValue>(expire))
+	{
+	}
+
+	~AccessExpireCache()
+	{
+	}
+
+private:
+	AccessExpireCache(const AccessExpireCache& aCache);
+	AccessExpireCache& operator = (const AccessExpireCache& aCache);
+};
+
+
+} // namespace Poco
+
+
+#endif