Reference

EventRouter Class Reference

#include <EventRouter.h>

Inheritance diagram for EventRouter:

Detailed Description

This class will handle distribution of events as well as management of timers.

Classes must inherit from EventListener and/or EventTrapper in order to receive events.

Use the global erouter instance of EventRouter to both send (post) and receive (subscribe/listen) to events. (except if you are posting from within a MotionCommand, in which case you should use MotionCommand::postEvent() so that it can correctly handle inter-process communication issues under Aperios (the Aibo's OS) -- under a Unix-based OS, this wouldn't be necessary.)

The events available for processing are listed in EventBase::EventGeneratorID_t. Each generator ID's documentation specifies how to interpret the source ID field, and whether you can expect events with that generator ID to be of a subclass of EventBase, such as TextMsgEvent or LocomotionEvent. Many generators send plain EventBase instances.

When multiple listeners are subscribed, the order in which an event is distributed among them is:

"Specific" listeners: any listener which specifies a particular source id. (doesn't matter if they specified type id as well)
- older listeners get events before more recently added listeners ("FIFO")
"General" listeners: those that subscribe to an entire generator
- older listeners get events before more recently added listeners ("FIFO")

...but if you're relying on that ordering, there probably should be a cleaner way to do whatever you're doing.

TimerEvents are generally only sent to the generator which requested them. So if EventListener A requests a timer (see addTimer()) with ID 0 at two second intervals, and B requests a timer with ID 0 at three second intervals, each will still only receive the timers they requested - no cross talk. The timer generator is unique in this regard, which is why it is built in as an integral component of the EventRouter. However, EventListener A can receive B's timers if it specifically wants to, via addListener(). See "Timers" below.

If an EventListener/EventTrapper subscribes to the same event source multiple times, it will receive multiple copies of the event. However, the first call to removeListener for a source will remove all subscriptions to that source.
Example: EventListener A subscribes to (buttonEGID,*,*), and twice to (buttonEGID,0,*).

If button 0 is pressed, A will get three copies of the event.
If button 1 is pressed, A will get one copy.
If removeListener(&A,buttonEGID) is called, the (buttonEGID,*,*) is removed, as well as both of (buttonEGID,0,*).
If removeListener(&A,buttonEGID,0) is called, both of (buttonEGID,0,*) are removed, but (buttonEGID,*,*) would be untouched.

Timers

addTimer() allows you to request an TimerEvent to be sent at some later point in time, possibly on a repeating basis. Timers are specific to the behavior which requests them, and you do not (and usually should not) call addListener() in order to receive a timer event.

There is an important different between addTimer() and addListener(timerEGID,...)! addTimer will "create" the timer, and will send the timer to the listener which created it when the timer expires. This means that as long as the listener in question does not call addListener(timerEGID), it will only receive its own timers. In other words, with this usage there is no confusion with timer cross-talk between listeners, because each listener is only receiving its own timers.

However, if a listener calls addListener(timerEGID), it will begin receiving all timer events from throughout the system. This allows you to have one behavior "eavesdrop" on another's timers. In order to determine which listener requested/created the timer, you can use the TimerEvent::getTarget() value.

So beware that if you call both addTimer() and addListener(foo,timerEGID), 'foo' will get two calls to processEvent() for its own timers, and one call for all other timers, and will have to know to call TimerEvent::getTarget() to distinguish its timers from other listener's timers (if it cares about the difference...)

Timers are sent to the requesting listener before being broadcast -- EventTrappers cannot filter a listener's own timers, but can prevent the timer from being broadcast to other listeners.

Event processing examples:

Posting events:

  //method A: basic event posting (EventBase instance is sent)
  erouter->postEvent(EventBase::aiEGID, 1234, EventBase::statusETID);

  //method B: specific event instance is posted (have to use this style to post a subclass)
  TextMsgEvent txt("hello world");
  erouter->postEvent(txt);
  // or can be done in one line:
  erouter->postEvent(TextMsgEvent("hello world"))

Receiving events:

  //given an EventListener subclass:
  class YourListener : public EventListener {
  public:
    virtual void processEvent(const EventBase& e) {
      std::cout << "Got: " << e.getName() << std::endl;
    }
  };

  YourListener yourList;

  // subscribes it to all EventBase::aiEGID events:
  erouter->addListener(&yourList, EventBase::aiEGID);

  // subscribes only to button activity from the head, but not other buttons:
  erouter->addListener(&yourList, EventBase::buttonEGID, ERS7Info::HeadButOffset);

Typically in a BehaviorBase subclass, you would just specify 'this' instead of '&yourList'.

Timer processing examples:

Requesting/Creating timers:

  YourListener yourList; // (any EventListener subclass)

  // sends a timer with source ID 123 every 5 seconds to yourList:
  erouter->addTimer(&yourList, 123, 5000);

  // sends a timer with ID 456 after 1 second, *no repeat, one time only*
  erouter->addTimer(&yourList, 456, 1000, false);

  // cancels the first timer
  erouter->removeTimer(&yourList, 123);

  // postpone/update the second timer's settings (*doesn't* create two timers with the same ID)
  erouter->addTimer(&yourList, 456, 2500, false);

Again, typically in a BehaviorBase subclass, you would just specify 'this' instead of '&yourList'.

See also:

EventBase::EventGeneratorID_t for a complete listing of all generators, as well as instructions on how to add new generators.

Tutorials:

Definition at line 151 of file EventRouter.h.

Public Member Functions

EventRouter ()

Constructs the router.

virtual ~EventRouter ()

just calls reset and removeAllTimers()

void reset ()

erases all listeners, trappers and timers, resets EventRouter

Posting/Processing Events

void postEvent (EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid, unsigned int dur=0)

recommended to create and post an event using current buffer setting

void postEvent (EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid, unsigned int dur, const std::string &n, float m)

recommended to create and post an event using current buffer setting

void postEvent (EventBase *e) ATTR_deprecated

deprecated -- pass by reference instead; this version posts the specified event and then deletes it after processing is complete

void postEvent (const EventBase &e)

posts the specified event, but doesn't delete it at the end -- equivalent to processEvent(e)

void processTimers ()

determines if timers need to be posted, and posts them if so.

void processEvent (const EventBase &e)

sends event to its trappers & listeners, but doesn't delete the event at the end (see also postEvent())

Listener/Trapper Recall

bool isListeningAny (EventListener *el, EventBase::EventGeneratorID_t egid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isListeningAny (EventListener *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isListeningAll (EventListener *el, EventBase::EventGeneratorID_t egid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isListeningAll (EventListener *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isListening (EventListener *el, EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isListening (EventListener *el, const EventBase &e)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isTrappingAny (EventTrapper *el, EventBase::EventGeneratorID_t egid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isTrappingAny (EventTrapper *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isTrappingAll (EventTrapper *el, EventBase::EventGeneratorID_t egid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isTrappingAll (EventTrapper *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isTrapping (EventTrapper *el, EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid)

returns true if the specified listener/trapper would receive any events that match the specified criteria

bool isTrapping (EventTrapper *el, const EventBase &e)

returns true if the specified listener/trapper would receive any events that match the specified criteria

Listener/Trapper Detection

bool hasListeners (EventBase::EventGeneratorID_t egid)

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

bool hasListeners (EventBase::EventGeneratorID_t egid, unsigned int sid)

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

bool hasListeners (EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid)

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

bool hasListeners (const EventBase &e)

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

Timer Management

void addTimer (EventListener *el, unsigned int sid, unsigned int delay, bool repeat=true)

adds a timer if it doesn't exist, or resets the timer if it already exists.

void addTimer (EventListener *el, const EventBase &e, bool repeat=true)

calls the other addTimer() with the event's source id and duration, doesn't check to see if the generator is timerEGID

void removeTimer (EventListener *el)

clears all pending timers for listener el; see remove()

void removeTimer (EventListener *el, unsigned int sid)

clears any pending timers with source id sid for listener el

void removeAllTimers ()

clears all timers for all listeners

unsigned int getNextTimer ()

returns time of next timer activation

Listener Management

void addListener (EventListener *el, EventBase::EventGeneratorID_t egid)

Adds a listener for all events from a given event generator.

void addListener (EventListener *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

Adds a listener for all types from a specific source and generator.

void addListener (EventListener *el, EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid)

Adds a listener for a specific source id and type from a given event generator.

void addListener (EventListener *el, const EventBase &e)

Uses the generator, source, and type fields of e to add a listener for that specific tuple.

void removeListener (EventListener *el)

stops sending ALL events to the listener -- does not remove pending timers however (may need to call removeTimer(el) as well); see remove()

void removeListener (EventListener *el, EventBase::EventGeneratorID_t egid)

stops sending specified events from the generator to the listener.

void removeListener (EventListener *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

stops sending specified events from the generator to the listener.

void removeListener (EventListener *el, EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid)

stops sending specified events from the generator to the listener.

void removeListener (EventListener *el, const EventBase &e)

Uses the generator, source, and type fields of e to remove a listener for that specific tuple.

void remove (EventListener *el)

stops all events and timers, shorthand for removeListener(el) and removeTimer(el); Note that trappers are separate, removeTrapper() is not called

Trapper Management

void addTrapper (EventTrapper *el, const EventBase &e)

Adds a trapper for a specific source id and type from a given event generator.

void addTrapper (EventTrapper *el, EventBase::EventGeneratorID_t egid)

Adds a trapper for all events from a given event generator.

void addTrapper (EventTrapper *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

Adds a trapper for all types from a specific source and generator.

void addTrapper (EventTrapper *el, EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid)

Adds a trapper for a specific source id and type from a given event generator.

void addTrapper (EventTrapper *el)

adds a trapper for ALL events

void removeTrapper (EventTrapper *el, const EventBase &e)

stops sending specified events from the generator to the trapper.

void removeTrapper (EventTrapper *el, EventBase::EventGeneratorID_t egid)

stops sending specified events from the generator to the trapper.

void removeTrapper (EventTrapper *el, EventBase::EventGeneratorID_t egid, unsigned int sid)

stops sending specified events from the generator to the trapper.

void removeTrapper (EventTrapper *el, EventBase::EventGeneratorID_t egid, unsigned int sid, EventBase::EventTypeID_t etid)

stops sending specified events from the generator to the trapper.

void removeTrapper (EventTrapper *el)

stops sending ALL events to the trapper

Protected Types

typedef std::vector< TimerEntry
* >::iterator timer_it_t

makes code more readable

Protected Member Functions

void chkTimers ()

just for debugging

void dispTimers ()

just for debugging

Protected Attributes

std::vector< TimerEntry * > timers

the list of timer entries being maintained, kept sorted by time they go active

EventMapper trappers

A mapping of which EventTrapper's should get a chance to trap the event.

EventMapper listeners

A mapping of which EventListener's should receive events.

std::queue< PostingStatus * > postings

stores calls to post() currently in progress -- may grow if one postEvent() triggers another; this allows us to finish processing of the original postEvent() before starting the second.

Classes

class EventMapper

Does the actual storage of the mapping between EventBase's and the EventListeners/EventTrappers who should receive them. More...

class PostingStatus

contains information regarding the progress of posting an event More...

struct TimerEntry

Contains all the information needed to maintain a timer by the EventRouter. More...

class TimerEntryPtrCmp

Used by STL to sort the timer list in order of activation time. More...

Member Typedef Documentation

typedef std::vector<TimerEntry*>::iterator EventRouter::timer_it_t [protected]

makes code more readable

Definition at line 303 of file EventRouter.h.

Constructor & Destructor Documentation

EventRouter::EventRouter ( )

Constructs the router.

Definition at line 10 of file EventRouter.cc.

virtual EventRouter::~EventRouter ( ) [inline, virtual]

just calls reset and removeAllTimers()

Definition at line 154 of file EventRouter.h.

Member Function Documentation

void EventRouter::addListener	(	EventListener *	el,
		const EventBase &	e
	)

Uses the generator, source, and type fields of e to add a listener for that specific tuple.

Definition at line 144 of file EventRouter.cc.

void EventRouter::addListener	(	EventListener *	el,
		EventBase::EventGeneratorID_t	egid,
		unsigned int	sid,
		EventBase::EventTypeID_t	etid
	)

Adds a listener for a specific source id and type from a given event generator.

Definition at line 136 of file EventRouter.cc.

void EventRouter::addListener	(	EventListener *	el,
		EventBase::EventGeneratorID_t	egid,
		unsigned int	sid
	)

Adds a listener for all types from a specific source and generator.

Definition at line 127 of file EventRouter.cc.

void EventRouter::addListener	(	EventListener *	el,
		EventBase::EventGeneratorID_t	egid
	)

Adds a listener for all events from a given event generator.

Definition at line 119 of file EventRouter.cc.

void EventRouter::addTimer	(	EventListener *	el,
		const EventBase &	e,
		bool	repeat = `true`
	)			`[inline]`

calls the other addTimer() with the event's source id and duration, doesn't check to see if the generator is timerEGID

Definition at line 222 of file EventRouter.h.

void EventRouter::addTimer	(	EventListener *	el,
		unsigned int	sid,
		unsigned int	delay,
		bool	repeat = `true`
	)

adds a timer if it doesn't exist, or resets the timer if it already exists.

timers are unique by EventListener and source ID - can't have two timers for the same el and sid
a delay of 0 with repeating will cause an event to be sent at every opportunity, use sparingly
a delay of -1U will call removeTimer() if it already exists, otherwise is ignored

Parameters:

	el	the EventListener to send the timer event to
	sid	the source ID to use on that event (if you need to send more info, send a pointer to a struct of your devising, typecasted as int)
	delay	the delay between the first (and future) calls
	repeat	set to true if you want to keep receiving this event, otherwise it will only send once

Definition at line 74 of file EventRouter.cc.

Referenced by addTimer(), NullTrans::DoStart(), ConnectionMadeTrans::DoStart(), PostureEditor::processEvent(), FlashIPAddrBehavior::processEvent(), BatteryMonitorBehavior::processEvent(), SensorObserverControl::RTViewControl::refresh(), PostureEditor::refresh(), NetworkStatusControl::refresh(), TimeOutTrans::resetTimer(), FreeMemReportControl::resetTimerFreq(), WalkControllerBehavior::runCommand(), UPennWalkControllerBehavior::runCommand(), FlashIPAddrBehavior::setupSequence(), and BatteryMonitorBehavior::startWarning().

void EventRouter::addTrapper ( EventTrapper * el )

adds a trapper for ALL events

Note that since timers are not broadcast, they cannot be trapped. Only the EventListener which requested the timer will receive that timer.

Definition at line 243 of file EventRouter.cc.

void EventRouter::addTrapper	(	EventTrapper *	el,
		EventBase::EventGeneratorID_t	egid,
		unsigned int	sid,
		EventBase::EventTypeID_t	etid
	)

Adds a trapper for a specific source id and type from a given event generator.

Note that since timers are not broadcast, they cannot be trapped. Only the EventListener which requested the timer will receive that timer.

Definition at line 233 of file EventRouter.cc.

void EventRouter::addTrapper	(	EventTrapper *	el,
		EventBase::EventGeneratorID_t	egid,
		unsigned int	sid
	)

Adds a trapper for all types from a specific source and generator.

Note that since timers are not broadcast, they cannot be trapped. Only the EventListener which requested the timer will receive that timer.

Definition at line 223 of file EventRouter.cc.

void EventRouter::addTrapper	(	EventTrapper *	el,
		EventBase::EventGeneratorID_t	egid
	)

Adds a trapper for all events from a given event generator.

Note that since timers are not broadcast, they cannot be trapped. Only the EventListener which requested the timer will receive that timer.

Definition at line 214 of file EventRouter.cc.

void EventRouter::addTrapper	(	EventTrapper *	el,
		const EventBase &	e
	)

Adds a trapper for a specific source id and type from a given event generator.

Note that only the broadcasted timers can be trapped. The EventListener which requested the timer will receive that timer before any trapping is done.

Definition at line 205 of file EventRouter.cc.

Referenced by Controller::activate(), addTrapper(), WorldStateVelDaemon::DoStart(), and Controller::takeLine().

void EventRouter::chkTimers ( ) [inline, protected]

just for debugging

Definition at line 307 of file EventRouter.h.

void EventRouter::dispTimers ( ) [inline, protected]

just for debugging

Definition at line 318 of file EventRouter.h.

Referenced by chkTimers().

unsigned int EventRouter::getNextTimer ( ) [inline]

returns time of next timer activation

Definition at line 228 of file EventRouter.h.

bool EventRouter::hasListeners ( const EventBase & e ) [inline]

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

Definition at line 214 of file EventRouter.h.

bool EventRouter::hasListeners	(	EventBase::EventGeneratorID_t	egid,
		unsigned int	sid,
		EventBase::EventTypeID_t	etid
	)			`[inline]`

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

Definition at line 213 of file EventRouter.h.

bool EventRouter::hasListeners	(	EventBase::EventGeneratorID_t	egid,
		unsigned int	sid
	)			`[inline]`

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

Definition at line 212 of file EventRouter.h.

bool EventRouter::hasListeners ( EventBase::EventGeneratorID_t egid ) [inline]

counts both listeners and trappers, so generators can tell if it even needs to bother generating an event...

Definition at line 211 of file EventRouter.h.

Referenced by addListener(), addTrapper(), hasListeners(), EventGeneratorBase::hasListeners(), removeListener(), and removeTrapper().

bool EventRouter::isListening	(	EventListener *	el,
		const EventBase &	e
	)			`[inline]`