dpp::event_router_t< T > Class Template Reference

Handles routing of an event to multiple listeners. Multiple listeners may attach to the event_router_t by means of operator(). Passing a lambda into operator() attaches to the event. More...

#include <event_router.h>

Public Member Functions
	event_router_t ()=default
	Construct a new event_router_t object. More...
	~event_router_t ()
	Destructor. Will cancel any coroutine awaiting on events. More...
void	call (const T &event) const
	Call all attached listeners. Listeners may cancel, by calling the event.cancel method. More...
bool	empty () const
	Returns true if the container of listeners is empty, i.e. there is nothing listening for this event right now. More...
	operator bool () const
	Returns true if any listeners are attached. More...
template<typename F >
event_handle	operator() (F &&fun)
	Attach a callable to the event, adding a listener. The callable should either be of the form void(const T &) or dpp::job(T) (the latter requires DPP_CORO to be defined), where T is the event type for this event router. More...
template<typename F >
event_handle	attach (F &&fun)
	Attach a callable to the event, adding a listener. The callable should either be of the form void(const T &) or dpp::job(T) (the latter requires DPP_CORO to be defined), where T is the event type for this event router. More...
bool	detach (const event_handle &handle)
	Detach a listener from the event using a previously obtained ID. More...

Protected Member Functions
void	set_warning_callback (std::function< void(const T &)> warning_function)
	Next handle to be given out by the event router. More...

Friends
class	cluster

Detailed Description

template<class T>
class dpp::event_router_t< T >

Handles routing of an event to multiple listeners. Multiple listeners may attach to the event_router_t by means of operator(). Passing a lambda into operator() attaches to the event.

Dispatchers of the event may call the call() method to cause all listeners to receive the event.

The empty() method will return true if there are no listeners attached to the event_router_t (this can be used to save time by not constructing objects that nobody will ever see).

The detach() method removes an existing listener from the event, using the event_handle ID returned by operator().

This class is used by the library to route all websocket events to listening code.

Example:

// Declare an event that takes log_t as its parameter
event_router_t<log_t> my_event;
 
// Attach a listener to the event
event_handle id = my_event([&](const log_t& cc) {
  std::cout << cc.message << "\n";
});
 
// Construct a log_t and call the event (listeners will receive the log_t object)
log_t lt;
lt.message = "foo";
my_event.call(lt);
 
// Detach from an event using the handle returned by operator()
my_event.detach(id);

Template Parameters

T	type of single parameter passed to event lambda derived from event_dispatch_t

Constructor & Destructor Documentation

event_router_t()

template<class T >

dpp::event_router_t< T >::event_router_t ( )

default

Construct a new event_router_t object.

~event_router_t()

template<class T >

dpp::event_router_t< T >::~event_router_t ( )

inline

Destructor. Will cancel any coroutine awaiting on events.

Exceptions

!	Cancelling a coroutine will throw a dpp::task_cancelled_exception to it. This will be caught in this destructor, however, make sure no other exceptions are thrown in the coroutine after that or it will terminate.

Member Function Documentation

attach()

template<class T >

template<typename F >

event_handle dpp::event_router_t< T >::attach

(

F &&

fun

)

Attach a callable to the event, adding a listener. The callable should either be of the form void(const T &) or dpp::job(T) (the latter requires DPP_CORO to be defined), where T is the event type for this event router.

Parameters

fun	Callable to attach to event

Returns

event_handle An event handle unique to this event, used to detach the listener from the event later if necessary.

call()

template<class T >

void dpp::event_router_t< T >::call ( const T &  event ) const

inline

Call all attached listeners. Listeners may cancel, by calling the event.cancel method.

Parameters

event

Class to pass as parameter to all listeners.

detach()

template<class T >

bool dpp::event_router_t< T >::detach ( const event_handle &  handle )

inline

Detach a listener from the event using a previously obtained ID.

Warning

You cannot call this within an event handler.

Parameters

handle

An ID obtained from operator()

Return values

true	The event was successfully detached
false	The ID is invalid (possibly already detached, or does not exist)

empty()

template<class T >

bool dpp::event_router_t< T >::empty ( ) const

inline

Returns true if the container of listeners is empty, i.e. there is nothing listening for this event right now.

Return values

true	if there are no listeners
false	if there are some listeners

operator bool()

template<class T >

dpp::event_router_t< T >::operator bool ( ) const

inline

Returns true if any listeners are attached.

This is the boolean opposite of event_router_t::empty().

Return values

true	if listeners are attached
false	if no listeners are attached

operator()()

template<class T >

template<typename F >

event_handle dpp::event_router_t< T >::operator()

(

F &&

fun

)

Attach a callable to the event, adding a listener. The callable should either be of the form void(const T &) or dpp::job(T) (the latter requires DPP_CORO to be defined), where T is the event type for this event router.

This has the exact same behavior as using attach.

See also

attach

Parameters

fun	Callable to attach to event

Returns

event_handle An event handle unique to this event, used to detach the listener from the event later if necessary.

set_warning_callback()

template<class T >

void dpp::event_router_t< T >::set_warning_callback ( std::function< void(const T &)>  warning_function )

inlineprotected

Next handle to be given out by the event router.

Set the warning callback object used to check that this event is capable of running properly

Parameters

warning_function

A checking function to call

Friends And Related Function Documentation

cluster

template<class T >

friend class cluster

friend