stor::ExpirableQueue< T, Policy > Class Template Reference

#include <ExpirableQueue.h>

Public Types
typedef Policy	PolicyType
typedef ConcurrentQueue< T, Policy >::SizeType	SizeType
typedef Policy::ValueType	ValueType

Public Member Functions
SizeType	clear ()
bool	clearIfStale (const utils::TimePoint_t &, SizeType &clearedEvents)
bool	deqNowait (ValueType &)
bool	empty () const
SizeType	enqNowait (T const &, const utils::TimePoint_t &now=utils::getCurrentTime())
	ExpirableQueue (SizeType maxsize=std::numeric_limits< SizeType >::max(), utils::Duration_t stalenessInterval=boost::posix_time::seconds(120), utils::TimePoint_t now=utils::getCurrentTime())
bool	full () const
void	setStalenessInterval (const utils::Duration_t &)
SizeType	size () const
bool	stale (const utils::TimePoint_t &) const
utils::Duration_t	stalenessInterval () const

Private Types
typedef ConcurrentQueue< T, Policy >	queue_t

Private Member Functions
	ExpirableQueue (ExpirableQueue &)
ExpirableQueue &	operator= (ExpirableQueue &)

Private Attributes
queue_t	events_
utils::Duration_t	stalenessInterval_
utils::TimePoint_t	stalenessTime_

Detailed Description

template<class T, class Policy>
class stor::ExpirableQueue< T, Policy >

Class template ExpirableQueue encapsulates a Queue (held through a shared_ptr, for inexpensive copying) and timing information. It keeps track of when the most recent called to deq was made.

Author:

mommsen

Revision:

1.7.4.1

Date:

2011/03/07 11:33:04

Definition at line 27 of file ExpirableQueue.h.

Member Typedef Documentation

template<class T, class Policy>

typedef Policy stor::ExpirableQueue< T, Policy >::PolicyType

Definition at line 30 of file ExpirableQueue.h.

template<class T, class Policy>

typedef ConcurrentQueue<T, Policy> stor::ExpirableQueue< T, Policy >::queue_t

private

Definition at line 111 of file ExpirableQueue.h.

template<class T, class Policy>

typedef ConcurrentQueue<T, Policy>::SizeType stor::ExpirableQueue< T, Policy >::SizeType

Definition at line 31 of file ExpirableQueue.h.

template<class T, class Policy>

typedef Policy::ValueType stor::ExpirableQueue< T, Policy >::ValueType

Definition at line 32 of file ExpirableQueue.h.

Constructor & Destructor Documentation

template<class T , class Policy >

stor::ExpirableQueue< T, Policy >::ExpirableQueue ( SizeType  maxsize = std::numeric_limits<SizeType>::max(), utils::Duration_t  stalenessInterval = boost::posix_time::seconds(120), utils::TimePoint_t  now = utils::getCurrentTime()  )

explicit

Create an ExpirableQueue with the given maximum size and given "time to stale", specified in seconds.

Definition at line 130 of file ExpirableQueue.h.

    :
    events_(maxsize),
    stalenessInterval_(stalenessInterval),
    stalenessTime_(now+stalenessInterval_)
  {
  }

template<class T, class Policy>

stor::ExpirableQueue< T, Policy >::ExpirableQueue ( ExpirableQueue< T, Policy > &  )

private

Member Function Documentation

template<class T , class Policy >

ExpirableQueue< T, Policy >::SizeType stor::ExpirableQueue< T, Policy >::clear ( void  )

inline

Clear the queue. Return the number of elements removed.

Definition at line 180 of file ExpirableQueue.h.

Referenced by python.Vispa.Views.WidgetView.WidgetView::closeEvent(), python.Vispa.Views.BoxDecayView.BoxDecayView::closeEvent(), python.Vispa.Share.FindAlgorithm.FindAlgorithm::findUsingFindDialog(), python.Vispa.Views.LineDecayView.LineDecayView::setDataObjects(), python.Vispa.Views.WidgetView.WidgetView::setDataObjects(), python.Vispa.Views.TreeView.TreeView::updateContent(), python.Vispa.Views.TableView.TableView::updateContent(), python.Vispa.Views.BoxDecayView.BoxDecayView::updateContent(), and python.Vispa.Views.PropertyView.PropertyView::updateContent().

  {
    return events_.clear();
  }  

template<class T , class Policy >

bool stor::ExpirableQueue< T, Policy >::clearIfStale ( const utils::TimePoint_t &  now, SizeType &  clearedEvents  )

inline

Return true if the queue is stale, and false if it is not. The queue is stale if its stalenessTime is before the given time. If the queue is stale, we also clear it and return the number of cleared events.

Definition at line 221 of file ExpirableQueue.h.

  {
    if (stalenessTime_ < now)
    {
      clearedEvents = clear();
      return true;
    }
    else
    {
      clearedEvents = 0;
      return false;
    }
  }

template<class T , class Policy >

bool stor::ExpirableQueue< T, Policy >::deqNowait

(

ValueType &

event

)

Try to remove an event from the queue, without blocking. If an event is available, return 'true' and set the output argument 'event'. If no event is available, return 'false'. In either case, update the staleness time to reflect this attempt to get an event.

Definition at line 143 of file ExpirableQueue.h.

References stor::utils::getCurrentTime().

  {
    stalenessTime_ = utils::getCurrentTime() + stalenessInterval_;
    return events_.deqNowait(event);
  }

template<class T , class Policy >

bool stor::ExpirableQueue< T, Policy >::empty ( void  ) const

inline

Return true if the queue is empty, and false otherwise.

Definition at line 188 of file ExpirableQueue.h.

Referenced by python.Vispa.Gui.VispaWidget.TextField::setAutosizeFont(), and python.Vispa.Gui.VispaWidget.TextField::setAutotruncate().

  {
    return events_.empty();
  }

template<class T , class Policy >

ExpirableQueue< T, Policy >::SizeType stor::ExpirableQueue< T, Policy >::enqNowait	(	T const &	event,
		const utils::TimePoint_t &	now = utils::getCurrentTime()
	)

Put an event onto the queue, if the queue is not stale at the given time. It respects the Policy of this queue that controls what is done in the case of a full queue. This does not affect the staleness time of this queue. Returns the number of dropped events.

Definition at line 151 of file ExpirableQueue.h.

  {
    if ( stale(now) )
    {
      events_.addExternallyDroppedEvents(1);
      return 1;
    }
    return events_.enqNowait(event);
  }  

template<class T , class Policy >

bool stor::ExpirableQueue< T, Policy >::full ( ) const

inline

Return true if the queue is full, and false otherwise.

Definition at line 204 of file ExpirableQueue.h.

  {
    return events_.full();
  }

template<class T, class Policy>

ExpirableQueue& stor::ExpirableQueue< T, Policy >::operator= ( ExpirableQueue< T, Policy > &  )

private

template<class T , class Policy >

void stor::ExpirableQueue< T, Policy >::setStalenessInterval ( const utils::Duration_t &  t )

inline

Set the staleness interval.

Definition at line 164 of file ExpirableQueue.h.

References matplotRender::t.

  {
    stalenessInterval_ = t;
  }

template<class T , class Policy >

ExpirableQueue< T, Policy >::SizeType stor::ExpirableQueue< T, Policy >::size ( void  ) const

inline

Get number of entries in queue

Definition at line 196 of file ExpirableQueue.h.

  {
    return events_.size();
  }

template<class T , class Policy >

bool stor::ExpirableQueue< T, Policy >::stale ( const utils::TimePoint_t &  now ) const

inline

Return true if the queue is stale at the given time, and false otherwise.

Definition at line 212 of file ExpirableQueue.h.

  {
    return (stalenessTime_ < now);
  }

template<class T , class Policy >

utils::Duration_t stor::ExpirableQueue< T, Policy >::stalenessInterval ( ) const

inline

Get the staleness interval.

Definition at line 172 of file ExpirableQueue.h.

  {
    return stalenessInterval_;
  }

Member Data Documentation

template<class T, class Policy>

queue_t stor::ExpirableQueue< T, Policy >::events_

private

Definition at line 113 of file ExpirableQueue.h.

template<class T, class Policy>

utils::Duration_t stor::ExpirableQueue< T, Policy >::stalenessInterval_

private

Time in seconds it takes for this queue to become stale.

Definition at line 115 of file ExpirableQueue.h.

template<class T, class Policy>

utils::TimePoint_t stor::ExpirableQueue< T, Policy >::stalenessTime_

private

Point in time at which this queue will become stale.

Definition at line 117 of file ExpirableQueue.h.