Comments on: running tasks in order with a task based sequence manager

By: a configurable, pluggable, thread safe prioritized bulk loader with object management at dpdk Open Source

Tue, 20 Jul 2010 12:27:26 +0000

[...] is a combination of a number of previously released dpdk packages, such as Collections and the task based sequence manager, making it incredibly powerful and easily extendable for customized use. Some of the core features [...]

By: Chris

Chris — Mon, 19 Apr 2010 03:01:21 +0000

This is gold. I wrote my own very simple sequence based function queue then stumbled onto this. You opened my eyes to what is more of a design pattern and what you have done obviously has its benefits. This will change the way I code everything from now on for the better, cheers!

By: Wait for user input in your sequence at dpdk Open Source

Wait for user input in your sequence at dpdk Open Source — Thu, 25 Feb 2010 12:39:09 +0000

[...] in your sequence Published by oskar on 25 February, 2010 in dpdk. We’ve been using the task based sequence for a while now and are very pleased with it. One thing we missed, was the possibility to listen to [...]

By: On using sequences and tasks with the DrupalService at dpdk Open Source

On using sequences and tasks with the DrupalService at dpdk Open Source — Mon, 12 Oct 2009 13:37:03 +0000

[...] Articles « running tasks in order with a task based sequence manager [...]

By: Benoît de Raemy

Benoît de Raemy — Fri, 02 Oct 2009 13:39:31 +0000

Hi Rolf,
Thank you very much, but I figure it out (as often in such case, I should have thought harder before bothering others for nuts) : all I had to do is to declare my ambiguous classes in extenso (with its “fully qualified class name”) in my mxml file each time I use it, and not only through an import of the whole class :
For example, the variable :
private var sequence: nl.dpdk.commands.tasks.Sequence;

And the constructor:
sequence = new nl.dpdk.commands.tasks.Sequence();

That way, Flex compiler knows exactly to which classes it refers, and is still free to get automatically the path for class references that are part of its “native” packages.

By: Rolf Vreijdenberger

Rolf Vreijdenberger — Fri, 02 Oct 2009 12:16:16 +0000

Hi Benoit,
thanks, glad that you can use our stuff, make sure to show us what you created!

as for the flex issue, we’ll get into that and try to fix it, but renaming Sequence is not an option for us as it is conceptually the best name for what it does.
As you might guess, our Sequence is a lot more powerful and universally applicable than what flex does, since it is only focused on tweening effects.

THat said, it should not be a problem since the compiler should resolve that it is in a different package. The ambiguity might be because of missing imports inside the package itself.
As I said, we’ll fix the issue soon.

In the meantime, if you do not use Sequences or Task with drupal, you could remove the tasks package in the nl.dpdk.services.gephyr package.

By: Benoît de Raemy

Benoît de Raemy — Thu, 01 Oct 2009 16:01:09 +0000

Hi,
First of all, thank you very much!! Your classes has been more than helpful to handle my data between my Drupal back-end and my flex front-end. I just had to add a comment service to your DrupalService and everything worked fine.
There’s only one little problem : as the name you use for the sequence classes is the same one as one used by the flex framework to handle some effects (mx.effects:Sequence), it “can’t resolve a multiname reference unambiguously”… Is there a way to get around this problem ? Do I have to rename the hundreds of reference “sequence” in my npdk package (and, if yes, is there a way to handle that automatically)? Or is there an other way to make sure my compiler doesn’t mix up between the two classes? Or, may be, you could be really-really cool to flex developer and fix that directly in your package…
Anyway, thank you again for your great job (and generosity) and I’m looking forward to showing you very soon what I achieved with your help (it’ll be peanuts to you, but as a beginner in flex and AS3, I’m very proud of it).

By: rolf vreijdenberger

rolf vreijdenberger — Tue, 29 Sep 2009 19:14:05 +0000

Hi Bart,
actually, you can pause the Sequence at any time via sequence.pause().
The currently executing task will finish and dispatch a TaskEvent when done, but the sequence will not continue. So your application state can react to Sequences but also the other way around. The use case you describe is taken care of

By: Bart

Bart — Fri, 25 Sep 2009 15:44:33 +0000

It’s looking good, can be very usefull. But to be able to use this in a more complicated environment a pause/resume feature would be great (or you’d get task/sequence-completion events from timed/framed tasks while everything else is paused and that will get very messy).

By: rolf vreijdenberger

rolf vreijdenberger — Tue, 01 Sep 2009 20:38:12 +0000

Hi Thijs,

thanks! I hope you’ll do some nice stuff with it.

There is no ITask interface, since you NEED to subclass/extend Task. Task itself has all the logic to be able to run it in a sequence. By subclassing Task and by overriding two methods, you only have to implement a little bit of logic and you cannot make any mistakes when you write your own subclasses, since the Task superclass takes care of all the necessary actions needed.

If you study the Task class you will see that it uses template methods, a technique where you specify a sequence of method calls inside a method (the template) and override only selected methods in the template method. This makes sure an order of calls is preserved (and thereby the logic), while allowing subclasses to introduce additional logic.