Design Advice for Representing Variables in LVOOP?

[lvb]

I am looking for some advice on class design and design pattern. I am designing a LabVIEW library that provides access to (and encapsulates ) a COM server.

The COM interface has two variable types:

• System Variable
  
• Node Variable
  

Common methods:

• Register/Unregister for Notifier
  
• Register/Unregister for Event
  
• Create
  
• Destroy
  
• Read
  
• Write
  

Common data:

• Name
  
• Units
  
• Comment
  

The variables differ in the refnum to the COM server and the possible data types that can be represented.

• System Variable
  
  • Integer
    
  • String
    
  • FloatInteger
    
  • ArrayFloat
    
  • Array
    

• Node Variable
  
  • Integer
    
  • String
    

I want to hide the existence of the System and Node variables from the user. They only need to know the variables that exist and the data types. I also want to restrict the user to only creating System Variables (within the COM interface).

What are your design recommendations for:

• Where to store the "data" of the variable?
  
• How to provide the user with read and write of different data types?
  
• How to expose these functions to the user of this API?