Forum

Replacing loong if chain

vvvv gamma question
#1

Hi there! I’m working on a live performance that uses websocket to communicate between my patch and the public via their smartphones.

I have a series of incoming messages of different type and I would like to do different things (namely: call different functions) based on the type of the message. Is there any good pattern for this?

In the previous version I used a loong chain of If statements, but it doesn’t feel right. Server side (node.js) i’ve approached this with Object Literals, using the type of the message as a key and the function as a value. (more here)

Could I do something similar also in gamma? Another way to approach this maybe could be something like the composition pattern, but then again, how to switch dynamically between nodes?

ciao ciao

#2

Hi,

This sound like StrategyPattern see example here by @sebescudie and the example I made for TextureFX basically shows how to switch between nodes using a simple factory.
https://discourse.vvvv.org/t/community-coding-design-patterns/17193/24

Also worth having a look at Reactive nodes to create a pipeline that would process messages as they arrive.

Definitely a sign that some refactoring is necessary but you should provide a patch so we can understand better the situation.

#3

Thanks a lot, the factory example is a perfect starting point!

#4

You can also use a dictionary with the message type as the key.

The value is then the logic that you want to execute specific to each message. it could be a delegate that does something or a class implementing a common interface.

but also, if it works as it is, it works… it might not look great, but sometimes that’s just what it is. :)

The correct solution on the VL side would be a switch statement, which we don’t have yet:

© vvvv group