OpenDDS::DCPS::PeriodicEvent Class Reference

#include <PeriodicEvent.h>

Inheritance diagram for OpenDDS::DCPS::PeriodicEvent:

Collaboration diagram for OpenDDS::DCPS::PeriodicEvent:

Public Member Functions
	PeriodicEvent (EventDispatcher_rch dispatcher, EventBase_rch event)
void	enable (const TimeDuration &period, bool immediate_dispatch=true, bool strict_timing=true)
void	disable ()
bool	enabled () const
void	handle_event ()
void	handle_cancel ()
Public Member Functions inherited from OpenDDS::DCPS::EventBase
virtual	~EventBase ()
virtual void	handle_error ()
	Only called when an exception is caught during handle_event. More...
void	operator() ()
Public Member Functions inherited from OpenDDS::DCPS::RcObject
virtual	~RcObject ()
virtual void	_add_ref ()
virtual void	_remove_ref ()
long	ref_count () const
WeakObject *	_get_weak_object () const

Private Member Functions
void	handle_event_scheduling ()

Private Attributes
ACE_Thread_Mutex	mutex_
ACE_Thread_Mutex	event_mutex_
WeakRcHandle< EventDispatcher >	dispatcher_
RcHandle< EventBase >	event_
TimeDuration	period_
bool	strict_timing_
MonotonicTimePoint	expiration_
long	timer_id_

Additional Inherited Members
Protected Member Functions inherited from OpenDDS::DCPS::RcObject
	RcObject ()

Detailed Description

PeriodicEvent is an event that is dispatched with a regular, repeating period

PeriodicEvent serves as a helpful utility class for repeatedly dispatching another base event at a regular, fixed interval. The PeriodicEvent takes both an EventDispatcher and a base event (c.f. EventBase) and handles the logic of scheduling, rescheduling, and canceling the base event with the EventDispatcher.

Definition at line 27 of file PeriodicEvent.h.

Constructor & Destructor Documentation

PeriodicEvent()

OpenDDS::DCPS::PeriodicEvent::PeriodicEvent	(	EventDispatcher_rch	dispatcher,
		EventBase_rch	event
	)

Creates a PeriodicEvent to handle scheduling a base event with an EventDispatcher

Parameters

dispatcher	the EventDispatcher to use for scheduling
event	the base event (c.f EventBase) to schedule for dispatch

Definition at line 18 of file PeriodicEvent.cpp.

 : dispatcher_(dispatcher)
 , event_(event)
 , strict_timing_(true)
 , timer_id_(0)
{
}

Member Function Documentation

disable()

void OpenDDS::DCPS::PeriodicEvent::disable

(

)

Disable the PeriodicEvent, canceling the scheduled base event if enabled.

Definition at line 50 of file PeriodicEvent.cpp.

References OpenDDS::DCPS::EventDispatcher::cancel(), dispatcher_, mutex_, and timer_id_.

{
  ACE_Guard<ACE_Thread_Mutex> guard(mutex_);
  if (timer_id_ > 0) {
    EventDispatcher_rch dispatcher = dispatcher_.lock();
    if (dispatcher) {
      if (dispatcher->cancel(timer_id_)) {
        timer_id_ = 0;
      }
    }
  }
}

enable()

void OpenDDS::DCPS::PeriodicEvent::enable	(	const TimeDuration &	period,
		bool	immediate_dispatch = true,
		bool	strict_timing = true
	)

Enable the PeriodicEvent to begin scheduling / rescheduling the base event using the internal EventDispatcher and the provided time period. If strict scheduling is requested, the elapsed time since the previous dispatch will not impact the time point provided for the next scheduled dispatch. Note: strict timing may potentially lead to CPU starvation if the dispatch takes longer than the requested period.

Parameters

period	the time period used to schedule / reschedule the base event
immediate_dispatch	set to true to immediately dispatch base event
strict_timing	set to true to strictly calculate scheduled dispatch times

Definition at line 26 of file PeriodicEvent.cpp.

References ACE_ERROR, OpenDDS::DCPS::EventDispatcher::dispatch(), dispatcher_, expiration_, LM_WARNING, OpenDDS::DCPS::log_level, mutex_, OpenDDS::DCPS::TimePoint_T< MonotonicClock >::now(), period_, OpenDDS::DCPS::rchandle_from(), OpenDDS::DCPS::EventDispatcher::schedule(), strict_timing_, timer_id_, and OpenDDS::DCPS::LogLevel::Warning.

{
  const MonotonicTimePoint now = MonotonicTimePoint::now();
  ACE_Guard<ACE_Thread_Mutex> guard(mutex_);
  if (timer_id_ < 1) {
    EventDispatcher_rch dispatcher = dispatcher_.lock();
    if (dispatcher) {
      const MonotonicTimePoint expiration = now + period;
      long id = dispatcher->schedule(rchandle_from(this), expiration);
      if (id > 0) {
        period_ = period;
        expiration_ = expiration;
        timer_id_ = id;
        strict_timing_ = strict_timing;
        if (immediate_dispatch) {
          dispatcher->dispatch(rchandle_from(this));
        }
      } else if (log_level >= LogLevel::Warning) {
        ACE_ERROR((LM_WARNING, "(%P|%t) PeriodicEvent::enable: failed to schedule\n"));
      }
    }
  }
}

enabled()

bool OpenDDS::DCPS::PeriodicEvent::enabled

(

)

const

Check to see if the PeriodicEvent is currently enabled

Returns

true if the PeriodicEvent is currently enabled

Definition at line 63 of file PeriodicEvent.cpp.

References mutex_, and timer_id_.

{
  ACE_Guard<ACE_Thread_Mutex> guard(mutex_);
  return timer_id_ > 0;
}

handle_cancel()

void OpenDDS::DCPS::PeriodicEvent::handle_cancel ( )

virtual

For use by EventDispatcher

Reimplemented from OpenDDS::DCPS::EventBase.

Definition at line 95 of file PeriodicEvent.cpp.

References event_, event_mutex_, OPENDDS_END_VERSIONED_NAMESPACE_DECL, and ACE_Guard< ACE_LOCK >::release().

{
  ACE_Guard<ACE_Thread_Mutex> guard(event_mutex_);
  if (event_) {
    RcHandle<EventBase> event_copy(event_);
    guard.release();
    event_copy->handle_cancel();
  }
}

handle_event()

void OpenDDS::DCPS::PeriodicEvent::handle_event ( )

virtual

For use by EventDispatcher

Implements OpenDDS::DCPS::EventBase.

Definition at line 84 of file PeriodicEvent.cpp.

References event_, event_mutex_, handle_event_scheduling(), and ACE_Guard< ACE_LOCK >::release().

{
  handle_event_scheduling();
  ACE_Guard<ACE_Thread_Mutex> guard(event_mutex_);
  if (event_) {
    RcHandle<EventBase> event_copy(event_);
    guard.release();
    event_copy->handle_event();
  }
}

handle_event_scheduling()

void OpenDDS::DCPS::PeriodicEvent::handle_event_scheduling ( )

private

Definition at line 69 of file PeriodicEvent.cpp.

References dispatcher_, expiration_, mutex_, OpenDDS::DCPS::TimePoint_T< MonotonicClock >::now(), period_, OpenDDS::DCPS::rchandle_from(), OpenDDS::DCPS::EventDispatcher::schedule(), strict_timing_, and timer_id_.

Referenced by handle_event().

{
  ACE_Guard<ACE_Thread_Mutex> guard(mutex_);
  timer_id_ = 0;
  EventDispatcher_rch dispatcher = dispatcher_.lock();
  if (dispatcher) {
    const MonotonicTimePoint expiration = (strict_timing_ ? expiration_ : MonotonicTimePoint::now()) + period_;
    long id = dispatcher->schedule(rchandle_from(this), expiration);
    if (id > 0) {
      expiration_ = expiration;
      timer_id_ = id;
    }
  }
}

Member Data Documentation

dispatcher_

WeakRcHandle<EventDispatcher> OpenDDS::DCPS::PeriodicEvent::dispatcher_

private

Definition at line 77 of file PeriodicEvent.h.

Referenced by disable(), enable(), and handle_event_scheduling().

event_

RcHandle<EventBase> OpenDDS::DCPS::PeriodicEvent::event_

private

Definition at line 78 of file PeriodicEvent.h.

Referenced by handle_cancel(), and handle_event().

event_mutex_

ACE_Thread_Mutex OpenDDS::DCPS::PeriodicEvent::event_mutex_

mutableprivate

Definition at line 76 of file PeriodicEvent.h.

Referenced by handle_cancel(), and handle_event().

expiration_

MonotonicTimePoint OpenDDS::DCPS::PeriodicEvent::expiration_

private

Definition at line 81 of file PeriodicEvent.h.

Referenced by enable(), and handle_event_scheduling().

mutex_

ACE_Thread_Mutex OpenDDS::DCPS::PeriodicEvent::mutex_

mutableprivate

Definition at line 75 of file PeriodicEvent.h.

Referenced by disable(), enable(), enabled(), and handle_event_scheduling().

period_

TimeDuration OpenDDS::DCPS::PeriodicEvent::period_

private

Definition at line 79 of file PeriodicEvent.h.

Referenced by enable(), and handle_event_scheduling().

strict_timing_

bool OpenDDS::DCPS::PeriodicEvent::strict_timing_

private

Definition at line 80 of file PeriodicEvent.h.

Referenced by enable(), and handle_event_scheduling().

timer_id_

long OpenDDS::DCPS::PeriodicEvent::timer_id_

private

Definition at line 82 of file PeriodicEvent.h.

Referenced by disable(), enable(), enabled(), and handle_event_scheduling().

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The documentation for this class was generated from the following files:

• PeriodicEvent.h
• PeriodicEvent.cpp