poco/Foundation/include/Poco/DynamicAny.h

//
// DynamicAny.h
//
// $Id: //poco/Main/Foundation/include/Poco/DynamicAny.h#2 $
//
// Library: Poco
// Package: Core
// Module:  DynamicAny
//
// Definition of the DynamicAny class.
//
// Copyright (c) 2007, 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 Poco_DynamicAny_INCLUDED
#define Poco_DynamicAny_INCLUDED


#include "Poco/Poco.h"
#include "Poco/DynamicAnyHolder.h"
#include <typeinfo>


namespace Poco {


class Foundation_API DynamicAny
	/// A DynamicAny allows to store data of different types and to convert between these types transparently.
	/// It's the reponsibility of the programmer to ensure that conversions are meaningful.
	/// For example: it is possible to convert between string and character. An empty string gets converted to 
	/// the char '\0', a non-empty string gets truncated to the very first character. Numeric values are truncated,
	/// no overflow/underflow errors are checked. A string value "false" can be converted to a boolean value false,
	/// any other string not "false" (not case sensitive) or "0" to true (e.g: "hi" -> true).
	///
	/// A DynamicAny can be created from a value of any type for which a
	/// specialization of DynamicAnyHolderImpl is available.
{
public:
	DynamicAny();
		/// Creates a DynamicAny holding an int with value 0.

	template <typename T> 
	DynamicAny(const T &val):
		_pHolder(new DynamicAnyHolderImpl<T>(val))
		/// Creates the DynamicAny from the given value.
	{
	}

	DynamicAny(const char* pVal);
		// Convenience constructor for const char* which gets mapped to a std::string internally, i.e. pVal is deep-copied.

	DynamicAny(const DynamicAny& other);
		/// Copy constructor.

	~DynamicAny();
		/// Destroys the DynamicAny.

	void swap(DynamicAny& other);
		/// Swaps the content of the this DynamicAny with the other DynamicAny.

	template <typename T> 
	void convert(T& val) const
		/// Invoke this method to perform conversion.
		///
		/// Example usage:
		///     DynamicAny any("42");
		///     int i;
		///     any.convert(i);
	{
		_pHolder->convert(val);
	}
	
	template <typename T> 
	T convert() const
		/// Invoke this method to perform conversion.
		///
		/// Example usage:
		///     DynamicAny any("42");
		///     int i = any.convert<int>();
	{
		T result;
		_pHolder->convert(result);
		return result;
	}

	template <typename T> 
	DynamicAny& operator = (const T& other)
		/// Assignment operator
	{
		DynamicAny tmp(other);
		swap(tmp);
		return *this;
	}
	
    const std::type_info& type() const;
		/// Returns the type information of the stored content.
	
private:
	DynamicAnyHolder* _pHolder;
};


} // namespace Poco


#endif // Poco_DynamicAny_INCLUDED