seda.sandStorm.core
Class ssTimer

java.lang.Object
  seda.sandStorm.core.ssTimer

All Implemented Interfaces:

java.lang.Runnable, ProfilableIF

public class ssTimer
extends java.lang.Object
implements java.lang.Runnable, ProfilableIF

The ssTimer class provides a mechanism for registering timer events that will go off at some future time. The future time can be specified in absolute or relative terms. When the timer goes off, an element is placed on a queue. There is no way to unregister a timer. Events will be delivered guaranteed, but the time that they are delivered may slip depending on stuff like how loaded the system is and all that.

WARNING: you should use cancelEvent to cancel timers that you no longer need, otherwise you will waste many, many cycles on unneeded timer firings. This was the bottleneck in vSpace and the DDS before we fixed it. For example, if you set a timer to go off on a cross-CPU task to detect failure, then if the task returns successfully, cancel the timer!

WARNING: delivery is NOT guaranteed given the use of enqueue_lossy().

Nested Class Summary

private static class	ssTimer.GQEString
static class	ssTimer.ssTimerEvent

Field Summary

private static int	DEBUG_LEVEL
private boolean	die_thread
private ssTimer.ssTimerEvent	head_event
private int	num_events
private java.lang.Object	sync_o
private ssTimer.ssTimerEvent	tail_event
private java.lang.Thread	thr

Constructor Summary

ssTimer()

Method Summary

void	cancelAll() Cancel all events, removing them from the queue.
void	cancelEvent(ssTimer.ssTimerEvent evt) Cancels the firing of this timer event.
private static boolean	DEBUG(int n)
void	doneWithTimer() Kills off this timer object, dropping all pending events on floor.
private void	insertEvent(ssTimer.ssTimerEvent newTimer)
static void	main(java.lang.String[] args)
private void	process_head() called by run() with a lock on sync_o and an event in the queue
int	profileSize() Return the profile size of this timer.
ssTimer.ssTimerEvent	registerEvent(java.util.Date the_date, QueueElementIF obj, SinkIF queue) Object obj will be placed on SinkIF queue no earlier than absolute time the_date.
ssTimer.ssTimerEvent	registerEvent(long millis, QueueElementIF obj, SinkIF queue) Object obj will be placed on SinkIF queue no earlier than millis milliseconds from now.
void	run() loop while die_thread==false, processing events as they are queued
int	size() How many events yet to fire?

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEBUG_LEVEL

private static final int DEBUG_LEVEL

See Also:

Constant Field Values

head_event

private ssTimer.ssTimerEvent head_event

tail_event

private ssTimer.ssTimerEvent tail_event

thr

private java.lang.Thread thr

sync_o

private java.lang.Object sync_o

die_thread

private boolean die_thread

num_events

private int num_events

Constructor Detail

ssTimer

public ssTimer()

Method Detail

DEBUG

private static final boolean DEBUG(int n)

registerEvent

public ssTimer.ssTimerEvent registerEvent(long millis,
                                          QueueElementIF obj,
                                          SinkIF queue)

Object obj will be placed on SinkIF queue no earlier than millis milliseconds from now.

Parameters:

millis - the number of milliseconds from now when the event will take place

obj - the object that will be placed on the queue

queue - the queue on which the object will be placed

registerEvent

public ssTimer.ssTimerEvent registerEvent(java.util.Date the_date,
                                          QueueElementIF obj,
                                          SinkIF queue)

Object obj will be placed on SinkIF queue no earlier than absolute time the_date.

Parameters:

the_date - the date when the event will take place - if this date is in the past, the event will happen right away

obj - the object that will be placed on the queue

queue - the queue on which the object will be placed

doneWithTimer

public void doneWithTimer()

Kills off this timer object, dropping all pending events on floor.

size

public int size()

How many events yet to fire?

profileSize

public int profileSize()

Return the profile size of this timer.

Specified by:

profileSize in interface ProfilableIF

cancelAll

public void cancelAll()

Cancel all events, removing them from the queue.

cancelEvent

public void cancelEvent(ssTimer.ssTimerEvent evt)

Cancels the firing of this timer event.

Parameters:

evt - the ssTimer.ssTimerEvent to cancel. This ssTimerEvent is returned to you when you call registerEvent

insertEvent

private void insertEvent(ssTimer.ssTimerEvent newTimer)

process_head

private void process_head()

called by run() with a lock on sync_o and an event in the queue

run

public void run()

loop while die_thread==false, processing events as they are queued

Specified by:

run in interface java.lang.Runnable

main

public static void main(java.lang.String[] args)