Code archives/Miscellaneous/Method Call Scheduler
This code has been declared by its author to be Public Domain code.
Download source code
| |||||
| This code allows you to 'schedule' object's methods to be called at some specified time later on. An ideal usage is for scheduling AI routines for large numbers of entities. The code has been designed to operate with minimum CPU overhead. No sorting or searching is required when scheduling calls and reading from the schedule, resulting in a very efficient system. | |||||
Rem
--------------------------------------------------------------------------------------------------------------
Event Scheduling Program
Bryan Fishman (USNavyFish), AUG 2008
This program was designed to provide an easy means of scheduling the execution of events within a game
or simulation. The system was designed for minimal overhead. It is not designed for extremely high
time sensitivity, and use of a time resolution less than one hundredth of a second is not recomended.
Essentially, the system provides an array where each cell represents one 'moment' of time. When events
are scheduled, this system places them in the appropriate cell which represents the moment of execution
for that event. The system then simply checks one cell per 'moment' and executes any event stored there.
In this manner, the system can support an extremely large number of concurrent and overlapping events, without
any performance loss, as the program is not required to loop through all scheduled events during every cycle.
This program provides two Custom Types:
A"TFutureEvent" type with the following functions, methods, and fields:
|| Field obj_:Object The targe objet whose method will be called
|| Field method_:TMethod This is the specific method which will be called
|| Field args_:Object[] An object array containing the arguments to be passed
||
|| Function Create:TFutureEvent( obj:Object,methodName:String,args:Object[] )
|| -This function creates and returns the FutureEvent.
|| -'methodName:String' is the exact name of the method that will be called
||
|| Function invoke:object() executes the FutureEvent.
A "TScheduler" type with the following functions and Globals (There are no Methods or locals)
|| Global TimeArray_Length:Int Size of the TimeArray (# of cells)
|| Global TimeArray_StepDuration:Float Duration of time represented by each cell
|| - Note that (Length * Duration) yields the furthest schedulable time
|| - i.e. 3600 cells of 1 second duration each allows events to be scheduled
|| up to one hour (inclusive) in advance.
||
|| Global TimeArray:TList[] Each cell stores a list of scheduled TFutureEvents
|| Global CurrentIndex:Int Current Index of the Time Array
|| Global ScheduleTimer:TTimer System Timer for Scheduler object
|| Global IsPaused:byte System Timer is paused if 1, is not paused if 0
||
|| Function Initialize(Length:Int = 3600 , Seconds:Float = 1)
|| - Call this once at the beginning of your program
|| - For a schedule that can store events up to 24 hours (inclusive) into the future,
|| and that has a schedule resolution of 0.1 seconds, use the following parameters:
|| Length = 3600 * 24 * 10
|| Seconds = 0.1
|| - Each Index specified by Length requires 4 bytes of memory. The above example requires
|| a total of ~3.3 MB of memory at runtime.
||
|| Function Begin()
|| - Activates the system timer
|| - Call this once you wish to actually begin schedule execution.
|| - Events may be scheduled both prior to and during the schedule's execution
||
|| Function ScheduleTimerHook:Object(id:Int, data:Object, context:Object)
|| - Internal funciton, intercepts system timer hook (returns null if intercepted)
|| - Calls the ScheduleAdvance and ScheduleExecute functions
||
|| Function ScheduleAdvance()
|| - Internal function, advances current Schedule Index
||
|| Function ScheduleExecute(index:Int)
|| - Internal Function, executes all events scheduled for current time index.
|| - This function removes all references to the scheduled events once executed
||
|| Function ScheduleEvent(event:TFutureEvent, SecondsDelay:Float)
|| - Call this function to schedule an event which will execute once in the future,
|| after the number of seconds specified by SecondsDelay has passed.
|| - For example, when called with SecondsDelay = 20, the passed event will execute
|| approximately 20 seconds after the "ScheduleEvent" function is called
|| - Scheduling accuracy reduces as "SecondsDelay" approaches the TimeArray_StepDuration
|| For best results, use a TimeArray_StepDuration value at least twice as short as
|| your quickest-scheduled events. For example, a program that regularly schedules
|| events at intervals as short as 1 second apart should use a StepDuration value of
|| at most 0.5 seconds. A value of 0.1 seconds wil provide much better accuracy.
||
|| Function ScheduleSetPause(command:byte)
|| This function sets the Scheduler's "IsPaused" flag.
|| When "IsPaused" = 1, normal execution occurs
|| When "IsPaused" = 0, the scheduler 'ignores' the schedule timer's tick event.
Example usages of the scheduler function:
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "textoutput" , ["You Called Me!"]) , 2)
||
||This calls obj1's "textoutput" method, with the input parameter "You Called Me!", in two seconds from this call.
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "add" , [String(1)]) , 4)
||
||This calls obj1's "add" method, with the input parameter of 1. Note the floating point value must be converted
||into a string to be accepted by the function. This event will execute in four seconds.
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "multiparam" , [String(4.3),String(17),"TEXT"]) , 20)
||
||This calls obj1's "multiparam" method, which accepts a float, an int, and a string as inputs to the method.
||Note how any non-string parameter inputs must be converted to strings using the String() function. This
||event will be executed in 20 seconds.
--------------------------------------------------------------------------------------------------------------
End Rem
SuperStrict
Type TFutureEvent
Field obj_:Object
Field method_:TMethod
Field args_:Object[]
Function Create:TFutureEvent( obj:Object,methodName:String,args:Object[] )
Local temp:TFutureEvent=New TFutureEvent
temp.obj_ = obj
temp.method_ = TTypeId.ForObject(obj).findMethod( methodName )
temp.args_ = args
Return temp
End Function
Method Invoke:Object()
Return method_.Invoke( obj_,args_ )
End Method
End Type
Type TScheduler
Global TimeArray_Length:Int
Global TimeArray_StepDuration:Float
Global TimeArray:TList[]
Global CurrentIndex:Int
Global ScheduleTimer:TTimer
Global IsPaused:Byte
Function Initialize(Length:Int = 3600 , Seconds:Float = 1)
DebugLog "Master Schedule Initialized"
DebugLog "Schedule Outlook: " + Length / Seconds + " Seconds"
DebugLog "Schedule Resolution: " + Seconds + " Seconds"
TimeArray_Length = Length + 1 'One is added so total duration is inclusive
TimeArray_StepDuration = Seconds
TimeArray = New TList[TimeArray_Length]
CurrentIndex = -1
End Function
Function Begin()
AddHook EmitEventHook , ScheduleTimerHook
ScheduleTimer = CreateTimer(1 / TimeArray_StepDuration)
DebugLog "Schedule Execution Commenced at System Time: " + CurrentTime()
End Function
Function ScheduleTimerHook:Object(id:Int, data:Object, context:Object)
Local ev:TEvent = TEvent(data)
If ev = Null Then Return Null
If ev.id = EVENT_TIMERTICK
If ev.source = ScheduleTimer
If IsPaused = 0
ScheduleAdvance()
DebugLog "ScheduleTimer Fires. Executing Index["+CurrentIndex+"]"
ScheduleExecute(CurrentIndex)
EndIf
Return Null
EndIf
EndIf
Return data
End Function
Function ScheduleAdvance()
CurrentIndex = (CurrentIndex + 1) Mod TimeArray_Length
End Function
Function ScheduleExecute(index:Int)
If TimeArray[index]
For Local event:TFutureEvent = EachIn TimeArray[index]
If event.obj_
event.invoke
Else
DebugLog "Object " + event.obj_.tostring() + " No longer Exists!"
EndIf
Next
TimeArray[index] = Null 'Removes all references to TList and stored TFutureEvents
EndIf
End Function
Function ScheduleEvent(event:TFutureEvent, SecondsDelay:Float)
Local index:Int
index = Ceil(SecondsDelay / TimeArray_StepDuration)
If index > TimeArray_Length
DebugLog "Critical Error!~nObject:~t" + event.obj_.tostring()
DebugLog "Scheduled Time (" + SecondsDelay+") converts to " + index + " future cells"
DebugLog "This exceeds the length of schedulable time (" + TimeArray_Length + " cells)"
End
EndIf
index :+ CurrentIndex + 1
index :Mod TimeArray_Length
If TimeArray[index] = Null Then TimeArray[index] = CreateList()
ListAddLast TimeArray[index] , event
DebugLog "Event Scheduled for object $" + event.obj_.tostring() + " in " + SecondsDelay + " seconds."
End Function
Function ScheduleSetPause(command:Byte)
IsPaused = command
End Function
End Type
Type TTestType
Field Value_:Float
Field name_:String
Function Create:TTestType(objname:String)
Local temp:TTestType = New TTestType
temp.name_= objname
temp.value_ = 0
Print temp.name_ + " Created: " + temp.value_
Return temp
End Function
Method add:Float(num:Float)
value_:+ num
Print name_ +"'s Counter increased to "+value_
End Method
Method textoutput:String(output:String)
Print name_ +" Says: "+output
End Method
End Type
Function KeyHook:Object(id:Int , data:Object , context:Object)
Local ev:TEvent = TEvent(data)
If ev = Null Then Return Null
Select ev.id
Case EVENT_KEYDOWN
Print "KEYDOWN~t" + ev.data
Select ev.data
Case 49
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "textoutput" , ["You Called Me!"]) , 1)
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "add" , [String(1)]) , 1)
Case 50
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "textoutput" , ["You Called Me!"]) , 2)
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "add" , [String(1)]) , 2)
Case 51
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "textoutput" , ["You Called Me!"]) , 4)
TScheduler.ScheduleEvent(TFutureEvent.Create(obj1 , "add" , [String(1)]) , 4)
Case 80
If TScheduler.IsPaused
TScheduler.ScheduleSetPause(0)
Else
TScheduler.ScheduleSetPause(1)
EndIf
End Select
Case EVENT_KEYUP
'Print "KEYUP~t"+ev.data
End Select
Return data
End Function
Graphics 640 , 480
AddHook EmitEventHook , Keyhook
TScheduler.Initialize(3600*24*4,0.25)
Global obj1:TTestType = TTestType.Create("Object1")
GCCollect
Print GCMemAlloced() + " Bytes Allocated"
Cls
Print "Press any key to begin! Make all key presses to the graphics window."
DrawText "Press any key to begin! Watch the console window.",0,0
Flip
WaitKey()
TScheduler.Begin()
Repeat
Cls
DrawText "Press 1, 2, or 3 to schedule an event for 1, 2, or 4 seconds in the future" , 0 , 0
DrawText "Watch the Console for output." , 0 , 30
DrawText "Observe the TimeArray cells advancing once every " + TScheduler.TimeArray_StepDuration + " seconds." , 0 , 60
DrawText "Now Press a key, wait the appropriate amount of time,",0,90
DrawText "And watch for the event response in the console!" , 20 , 110
Flip
Until KeyHit(key_escape)
End |
Comments
None.
Code Archives Forum
   |