Bellringer Class Reference

Manages and activates time-triggered activities. More...

#include <bellringer.h>

Collaboration diagram for Bellringer:

Public Member Functions
void	check ()
	Checks whether there are bells to be rung.
void	job (Bell *bell, unsigned int ms)
	Passes a bell to the bellringer to be rung after ms milliseconds.
void	cancel (Bell *bell)
	Cancel ticking & ringing a bell.
unsigned int	residual (Bell *bell)
	Returns the remaining time until bell will ring.
bool	bellPending ()
	Checks whether there are enqueued bells.

Private Attributes
Queue< Bell >	bells
	List of bells currently managed.

Detailed Description

Manages and activates time-triggered activities.

The Bellringer is regularly activated and checks whether any of the bells should ring. The bells are stored in a Queue<Bell> that is managed by the Bellringer. A clever implementation avoids iterating through the whole list for every iteration by keeping the bells sorted and storing delta times. This approach leads to a complexity of O(1) for the method called by the timer interrupt in case no bells need to be rung.

Member Function Documentation

bellPending()

bool Bellringer::bellPending

(

)

Checks whether there are enqueued bells.

Returns

true if there are enqueued bells, false otherwise

cancel()

void Bellringer::cancel

(

Bell *

bell

)

Cancel ticking & ringing a bell.

Parameters

bell	Bell that should not be rung.

check()

void Bellringer::check

(

)

Checks whether there are bells to be rung.

Every call to check elapses a tick. Once such a tick reduces a bells remaining time to zero, the bell will be rung.

job()

void Bellringer::job	(	Bell *	bell,
		unsigned int	ms )

Passes a bell to the bellringer to be rung after ms milliseconds.

Parameters

bell	Bell that should be rung after ms milliseconds
ms	number of milliseconds that should be waited before ringing the bell

residual()

unsigned int Bellringer::residual

(

Bell *

bell

)

Returns the remaining time until bell will ring.

Parameters

bell	The bell for which the remaining time should be returned

Returns

Remaining time in milliseconds

Optional

Implement Method

Member Data Documentation

bells

Queue<Bell> Bellringer::bells

private

List of bells currently managed.

This list contains non-expired bells enqueued by job(). These bells will be checked on every call to check().

All elements that should be inserted into a Queue instance are required to be derived from Queue<Bell>::Node.

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

• sync/bellringer.h
• sync/bellringer.cc