Observers

Observer subscribes on Observable and obtains values provided by Observable. More...

Concepts
concept	rpp::constraint::observer_strategy
	Concept to define strategy to override observer behavior. Strategy must be able to handle all observer's callbacks: on_next/on_error/on_completed.

Classes
class	rpp::dynamic_observer< Type >
	Type-erased version of the rpp::observer. Any observer can be converted to dynamic_observer via rpp::observer::as_dynamic member function. More...
class	rpp::observer< Type, Strategy >
	Base class for any observer used in RPP. It handles core callbacks of observers. Objects of this class would be passed to subscribe of observable. More...

Typedefs
template<constraint::decayed_type Type, std::invocable< Type > OnNext, std::invocable< const std::exception_ptr & > OnError, std::invocable<> OnCompleted>
using	rpp::lambda_observer = observer<Type, details::observers::lambda_strategy<Type, OnNext, OnError, OnCompleted>>
	Observer specialized with passed callbacks. Most easiesest way to construct observer "on the fly" via lambdas and etc.

Functions
template<constraint::decayed_type Type, std::invocable< Type > OnNext, std::invocable< const std::exception_ptr & > OnError = rpp::utils::rethrow_error_t, std::invocable<> OnCompleted = rpp::utils::empty_function_t<>>
auto	rpp::make_lambda_observer (OnNext &&on_next, OnError &&on_error={}, OnCompleted &&on_completed={}) -> lambda_observer< Type, std::decay_t< OnNext >, std::decay_t< OnError >, std::decay_t< OnCompleted > >
	Constructs observer specialized with passed callbacks. Most easiesest way to construct observer "on the fly" via lambdas and etc.
template<constraint::decayed_type Type, std::invocable< Type > OnNext, std::invocable< const std::exception_ptr & > OnError = rpp::utils::rethrow_error_t, std::invocable<> OnCompleted = rpp::utils::empty_function_t<>>
auto	rpp::make_lambda_observer (const rpp::composite_disposable_wrapper &d, OnNext &&on_next, OnError &&on_error={}, OnCompleted &&on_completed={}) -> lambda_observer_with_disposable< Type, std::decay_t< OnNext >, std::decay_t< OnError >, std::decay_t< OnCompleted > >
	Constructs observer specialized with passed callbacks. Most easiesest way to construct observer "on the fly" via lambdas and etc.

Detailed Description

Observer subscribes on Observable and obtains values provided by Observable.

Observer is kind of wrapper over 3 core functions:

• on_next(T) - callback with new emission provided by observable
• on_error(err) - failure termination callback with reason of failure of observable (why observable can't continue processing)
• on_completed() - succeed termination callback - observable is done, no any future emissions from this

  See also

  https://reactivex.io/documentation/observable.html

Typedef Documentation

lambda_observer

template<constraint::decayed_type Type, std::invocable< Type > OnNext, std::invocable< const std::exception_ptr & > OnError, std::invocable<> OnCompleted>

using rpp::lambda_observer = observer<Type, details::observers::lambda_strategy<Type, OnNext, OnError, OnCompleted>>

Observer specialized with passed callbacks. Most easiesest way to construct observer "on the fly" via lambdas and etc.

Template Parameters

Type	of value this observer can handle
OnNext	is type of callback to handle on_next(const Type&) and on_next(Type&&)
OnError	is type of callback to handle on_error(const std::exception_ptr&)
OnCompleted	is type of callback to handle on_completed()

Function Documentation

make_lambda_observer() [1/2]

template<constraint::decayed_type Type, std::invocable< Type > OnNext, std::invocable< const std::exception_ptr & > OnError = rpp::utils::rethrow_error_t, std::invocable<> OnCompleted = rpp::utils::empty_function_t<>>

auto rpp::make_lambda_observer	(	const rpp::composite_disposable_wrapper &	d,
		OnNext &&	on_next,
		OnError &&	on_error = {},
		OnCompleted &&	on_completed = {} ) -> lambda_observer_with_disposable<Type, std::decay_t<OnNext>, std::decay_t<OnError>, std::decay_t<OnCompleted>>

Constructs observer specialized with passed callbacks. Most easiesest way to construct observer "on the fly" via lambdas and etc.

Template Parameters

Type	of value this observer can handle

Parameters

d	is disposable to attach to resulting observer
on_next	is callback to handle on_next(const Type&) and on_next(Type&&)
on_error	is callback to handle on_error(const std::exception_ptr&)
on_completed	is callback to handle on_completed()

make_lambda_observer() [2/2]

template<constraint::decayed_type Type, std::invocable< Type > OnNext, std::invocable< const std::exception_ptr & > OnError = rpp::utils::rethrow_error_t, std::invocable<> OnCompleted = rpp::utils::empty_function_t<>>

auto rpp::make_lambda_observer	(	OnNext &&	on_next,
		OnError &&	on_error = {},
		OnCompleted &&	on_completed = {} ) -> lambda_observer<Type, std::decay_t<OnNext>, std::decay_t<OnError>, std::decay_t<OnCompleted>>

Constructs observer specialized with passed callbacks. Most easiesest way to construct observer "on the fly" via lambdas and etc.

Template Parameters

Type	of value this observer can handle

Parameters

on_next	is callback to handle on_next(const Type&) and on_next(Type&&)
on_error	is callback to handle on_error(const std::exception_ptr&)
on_completed	is callback to handle on_completed()