Chain: Delayed function calling [updated]

Mark Knol — Sat, 14 Nov 2009 12:00:36 +0000

I created a useful util-class to make delayed function calling easy. You can make a chain of functions, by adding them with a delay in milliseconds. This chain can be executed multiple times, even in reversed order.

Let’s take a look at a simple example of Chain.

var myChain:Chain = new Chain();    
 myChain.addEventListener( Event.COMPLETE, onComplete);
 myChain.add(one, 2000).add(two, 500).add(three, 1000).play(2);
function one():void { trace("one") }
 function two():void { trace("two") }
 function three():void { trace("three") }
 function onComplete(e:Event):void { trace("done.") }
/* trace output:
 one two three one two three done.
 */
  

What is happening here? At the first line we are instantiating the class, and the second line represents what chain does. There is a public function called ‘add’, which is an important part of the class. add(one, 2000) means: execute a function called ‘one’ after 2000 milliseconds. add(two,500).add(three,1000) are functions that are called after one is finished, with other delays. You can create your own rhythm/sequence/pattern. At the end we see play(2), which means: Execute the sequence of functions defined before, and repeat them 2 times. After that, dispatch event COMPLETE.

So that’s basically it. A cool part is you can play it reversed, using playReversed(). I am inspired by jQuery (which has nothing to do with this) to enable the ability to stick functions, but thats optional.

 myChain.playReversed(2);
/* trace output:
 three two one three two one
 */
  

Of course you can pauze/continue when you are playing, by calling stop() / doContinue(), and you can determine if it is currently playing using the isPlaying-getter.

These are all the public functions.

/// Constructor
publicfunction Chain()
/// Adds a function at a specified interval (in milliseconds).
 public function add(func:Function, delay:Number = 0):Chain
/// Start playing the sequence and calling functions
 public function play(repeatCount:int = 0):void
/// Start playing the sequence reversed
 public function playReversed(repeatCount:int = 0):void
/// Clears sequence list. Data will be removed.
 public function clear():Chain
/// Stop playing, use doContinue to play futher from current point
 public function stop():void
/// Continue playing after a stop
 public function doContinue():Chain
/// Reset indexes
 public function reset():void
/// Returns the string representation of the Chain private vars.
 public function toString():String
/// Return chain is playing, stopped or completed
 public function get isPlaying():Boolean
  

Hope you like it, let me know if you like to see extra/other related features.

Download: Chain (googlecode)

Updates
- Private functions are protected
- add-functions is now add(function, delay), where function is required.
- Class now extends EventDispatcher and play/playReversed dispatches Event.COMPLETE after playing sequence, instead of calling onComplete function
- Cleaned up code

Stroep » chain

Chain: Delayed function calling [updated]