//
// AbstractDelegate.h
//
// Library: Foundation
// Package: Events
// Module:  AbstractDelegate
//
// Implementation of the AbstractDelegate template.
//
// Copyright (c) 2006-2011, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_AbstractDelegate_INCLUDED
#define Foundation_AbstractDelegate_INCLUDED


#include "Poco/Foundation.h"


namespace Poco {


template <class TArgs>
class AbstractDelegate
	/// Base class for Delegate and Expire.
{
public:
	AbstractDelegate() = default;

	AbstractDelegate(const AbstractDelegate & /*del*/) = default;
	AbstractDelegate& operator=(const AbstractDelegate &) = default;

	virtual ~AbstractDelegate() = default;

	virtual bool notify(const void* sender, TArgs& arguments) = 0;
		/// Invokes the delegate's callback function.
		/// Returns true if successful, or false if the delegate
		/// has been disabled or has expired.

	virtual bool equals(const AbstractDelegate& other) const = 0;
		/// Compares the AbstractDelegate with the other one for equality.

	virtual AbstractDelegate* clone() const = 0;
		/// Returns a deep copy of the AbstractDelegate.

	virtual void disable() = 0;
		/// Disables the delegate, which is done prior to removal.

	virtual const AbstractDelegate* unwrap() const
		/// Returns the unwrapped delegate. Must be overridden by decorators
		/// like Expire.
	{
		return this;
	}
};


template <>
class AbstractDelegate<void>
	/// Base class for Delegate and Expire.
{
public:
	AbstractDelegate() = default;

	AbstractDelegate(const AbstractDelegate &) = default;
	AbstractDelegate& operator=(const AbstractDelegate &) = default;

	virtual ~AbstractDelegate() = default;

	virtual bool notify(const void* sender) = 0;
		/// Invokes the delegate's callback function.
		/// Returns true if successful, or false if the delegate
		/// has been disabled or has expired.

	virtual bool equals(const AbstractDelegate& other) const = 0;
		/// Compares the AbstractDelegate with the other one for equality.

	virtual AbstractDelegate* clone() const = 0;
		/// Returns a deep copy of the AbstractDelegate.

	virtual void disable() = 0;
		/// Disables the delegate, which is done prior to removal.

	virtual const AbstractDelegate* unwrap() const
		/// Returns the unwrapped delegate. Must be overridden by decorators
		/// like Expire.
	{
		return this;
	}
};


} // namespace Poco


#endif // Foundation_AbstractDelegate_INCLUDED
