new trunk (base for 1.5)

windows build only

Foundation/include/Poco/MetaObject.h

@@ -0,0 +1,223 @@
+//
+// MetaObject.h
+//
+// $Id: //poco/1.4/Foundation/include/Poco/MetaObject.h#1 $
+//
+// Library: Foundation
+// Package: SharedLibrary
+// Module:  ClassLoader
+//
+// Definition of the MetaObject class.
+//
+// Copyright (c) 2004-2006, 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_MetaObject_INCLUDED
+#define Foundation_MetaObject_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include "Poco/Exception.h"
+#include "Poco/SingletonHolder.h"
+#include <set>
+
+
+namespace Poco {
+
+
+template <class B>
+class AbstractMetaObject
+	/// A MetaObject stores some information
+	/// about a C++ class. The MetaObject class
+	/// is used by the Manifest class.
+	/// AbstractMetaObject is a common base class
+	/// for all MetaObject in a rooted class hierarchy.
+	/// A MetaObject can also be used as an object
+	/// factory for its class.
+{
+public:
+	AbstractMetaObject(const char* name): _name(name)
+	{
+	}
+
+	virtual ~AbstractMetaObject()
+	{
+		for (typename ObjectSet::iterator it = _deleteSet.begin(); it != _deleteSet.end(); ++it)
+		{
+			delete *it;
+		}
+	}
+
+	const char* name() const
+	{
+		return _name;
+	}
+
+	virtual B* create() const = 0;
+		/// Create a new instance of a class.
+		/// Cannot be used for singletons.
+		
+	virtual B& instance() const = 0;
+		/// Returns a reference to the only instance
+		/// of the class. Used for singletons only.
+
+	virtual bool canCreate() const = 0;
+		/// Returns true iff the create method can be used
+		/// to create instances of the class.
+		/// Returns false if the class is a singleton.
+
+	virtual void destroy(B* pObject) const
+		/// If pObject was owned by meta object, the
+		/// ownership of the deleted object is removed
+		/// and the object is deleted.
+	{
+		typename ObjectSet::iterator it = _deleteSet.find(pObject);
+		
+		if (it != _deleteSet.end())
+		{
+			_deleteSet.erase(pObject);
+			delete pObject;
+		}
+	}
+
+	B* autoDelete(B* pObject) const
+		/// Give ownership of pObject to the meta object.
+		/// The meta object will delete all objects it owns
+		/// when it is destroyed.
+		///
+		/// Returns pObject.
+	{
+		if (this->canCreate()) // guard against singleton
+		{
+			poco_check_ptr (pObject);
+			_deleteSet.insert(pObject);
+		}
+		else throw InvalidAccessException("Cannot take ownership of", this->name());
+
+		return pObject;
+	}
+
+	virtual bool isAutoDelete(B* pObject) const
+		/// Returns true if the object is owned
+		/// by meta object.
+		///
+		/// Overloaded in MetaSingleton - returns true
+		/// if the class is a singleton.
+	{
+		return _deleteSet.find(pObject) != _deleteSet.end();
+	}
+
+private:
+	AbstractMetaObject();
+	AbstractMetaObject(const AbstractMetaObject&);
+	AbstractMetaObject& operator = (const AbstractMetaObject&);
+
+	typedef std::set<B*> ObjectSet;
+	
+	const char* _name;
+	mutable ObjectSet _deleteSet;
+};
+
+
+template <class C, class B>
+class MetaObject: public AbstractMetaObject<B>
+	/// A MetaObject stores some information
+	/// about a C++ class. The MetaObject class
+	/// is used by the Manifest class.
+	/// A MetaObject can also be used as an object
+	/// factory for its class.
+{
+public:
+	MetaObject(const char* name): AbstractMetaObject<B>(name)
+	{
+	}
+
+	~MetaObject()
+	{
+	}
+
+	B* create() const
+	{
+		return new C;
+	}
+	
+	B& instance() const
+	{
+		throw InvalidAccessException("Not a singleton. Use create() to create instances of", this->name());
+	}
+	
+	bool canCreate() const
+	{
+		return true;
+	}
+};
+
+
+template <class C, class B> 
+class MetaSingleton: public AbstractMetaObject<B> 
+	/// A SingletonMetaObject disables the create() method
+	/// and instead offers an instance() method to access
+	/// the single instance of its class. 
+{ 
+public: 
+	MetaSingleton(const char* name): AbstractMetaObject<B>(name) 
+	{
+	}
+	
+	~MetaSingleton() 
+	{
+	}
+	
+	B* create() const
+	{
+		throw InvalidAccessException("Cannot create instances of a singleton class. Use instance() to obtain a", this->name());
+	}
+	
+	bool canCreate() const
+	{
+		return false;
+	}
+
+	B& instance() const
+	{
+		return *_object.get();
+	}
+      
+	bool isAutoDelete(B* pObject) const
+	{
+		return true;
+	}
+
+private: 
+	mutable SingletonHolder<C> _object; 
+}; 
+
+
+} // namespace Poco
+
+
+#endif // Foundation_MetaObject_INCLUDED