by Reference OO Desing

[D60]

Hello!

I am looking for some documentation with examples about Labview by Value and by Reference OO Design. Mostly, I interested in by Ref. OO Desing.

So I would be greatfuly If you could send me some useful links, examples.

Thank you!

[cschneider]

labview is normally "by value"...what you can do if you like to pass some objects by reference, you can use single-element queues or DVR (data value references) to pass your objects around in your code...just search in labview for these terms.

[MikaelH]

You can download GOOP Development Suite, and create some classes to see the different ways of implementing this.

http://www.symbio.com/products/trial/

KEY: COMM-UNIT-YEDI-TION-2010

Here are some demos videos you can have a look at.

http://goop.endevo.net/GDS/videos/GDSFeatures
http://goop.endevo.net/GDS/videos/GettingStarted
http://goop.endevo.net/GDS/videos/GOOP4Demo

Cheers,

Mikael

[D60]

Oh! Yes!!

Thanks!!!!

[F._Schubert]

As a general rule, in 80 or 90% you can use the native by-val design. So don't try to make everything by-ref as in other OOP languages.

By-ref has two flavours (only using DVR, neglecting SEQ):

* Your private data is a DVR to a type def. All accessors use the IPE structure to access the data stored in the DVR.

* Put your object in the DVR.

There is a lot of discussion on these designs on LAVA, but of course nothing like a tutorial but an advanced brainstorming.

Felix

[MikaelH]

In my case the rule "As a general rule, in 80 or 90%, you can use the native by-val design" doesn’t apply.
Were I found OO serving the best purpose is in the instrument layer (HAL), there we have around 100 classes, and there I don’t want to use by value. Normally my test application uses 10-20 different driver classes and around 5 higher level classes, plus my Top application. So for me it about 60-80% that has to be reference classes. And the 5 higher level classes usually use a Singleton design pattern so then I’m close to 90% of them being reference classes.

But this is just me. 

Cheers,

Mikael