HAL design issue

[Quiztus2]

I play around with a hardware abstraction layer. Right now I am stuck with my abstract init VI.

It seems I can't override my abstract init VI in child classes with inputs that are also children of the original init VI.

Since I can't have two dynamic inputs,

any suggestions for having a generic top level Init that accepts the device and a configuration object are welcome.

Error: This VI doesn't match other VIs in the method, Connector Pane Terminal(s) are different.

[ZYOng]

A few alternatives:

1. Use generic parameters : either the path of an INI file, or a variant (the child method will know how to cast it back to a cluster), or a string (XML or JSON)...

2. Make property node accessors for your class, initialize the parameters you need, and then call init() with no parameters

Reference: dealing with input types on dynamic dispatch - Object-Oriented Programming

[Quiztus2]

You ticked me in the right direction. Since the Specific FGEN knows which Configure object it can handle, I can cast the IConfigure to the correct IConfigureViaSessionHandle type inside it's Init VI. I will follow that path and will check where it brings me.

[crossrulz]

What I do is pass in a JSON string for the object to be created.  The first thing in that JSON object is the class name.  I can use that and some string manipulation to dynamically load the desired class.  I can later set the class type on the wire to a parent or a child.

I initially used an INI file for my configuration, but I eventually concluded that I needed a hierarchical format to properly define my devices and instruments.  I allowed for XML, then got hooked on JSON.  I recently removed the XML support because I thought JSON was so much better.

[Quiztus2]

I like the approach of JSON configuration files. They seem reasonable for having changing configurations within the same device type.