The TCallbackCapable class provides a base abstract interface to enable callback capability on PIC classes. More...

Inheritance diagram for TCallbackCapable< DelegateType, _ID >:

Public Types
using	Delegate = DelegateType

Public Member Functions
	TCallbackCapable (const DelegateType &iDelegate=DelegateType())

	TCallbackCapable (typename DelegateType::tFptr iDelegateFPTR)

const DelegateType &	GetDelegate () const

template<typename ... Args>
void	Invoke (Args ... args) const

void	SetDelegate (const DelegateType &iDelegate)

void	SetDelegate (const TCallbackCapable< DelegateType, _ID > &iOther)

void	SetDelegate (typename DelegateType::tFptr iDelegateFPTR)

Detailed Description

template<class DelegateType, int _ID = 0>
class TCallbackCapable< DelegateType, _ID >

Why is TCallbackCapable implemented as a class designed to be inherited from:

The other solution is to make it a member of the classes that need a delegate, this may seem simpler, but then it requires more code to be able to change the delegate during the object lifetime. This way, the object inherits the SetDelegate method. You can still have more than one delegate, you just need to inherit multiple times from the TCallbackCapable with a different DelegateType. ( Although, most client want to inherit TCallbackCapable privately.

In case you need multiple delegates of the same type, it is forbidden to inherit directly multiple time from the same base. So that's why the _ID arg is provided, it differentiates the bases artificially and allows to have multiple same delegates for different purposes.

For simplicity, a macro is provided below, see:

ULIS_DECLARE_SIMPLE_DELEGATE
ULIS_DECLARE_SIMPLE_DELEGATE_SPEC

it provides default template instanciation and export, as well as a typedef such as "FOnValueChanged", which is intented to be the main alias used to acces the TCallbackCapable part of the PIC that uses it. In case of multiple TCallbackCapable, Invoke() calls will be ambiguous and need to be prefixed by the alias:: identifier.

No automatic wrappers are provided to automate callback calls, because it is not possible to know in advance which delegate must be called, or if it is necessary in all methods ( such as getters ), and it would also be problematic in const methods.

TCallbackCapable is not supposed to be instanciated, but it's still possible to do so if you want to chose to use it by composition instead of inheritance, and for simplicity the typedefed TCallbackCapable can be used directly as input parameter in client classes and needs to be able to be default- constructed as a default input parameter, which requires it to be instanciable in global scope.