Building a structure/object in a place other than the constructor
- by Vishal Naidu
I have different types of objects representing the same business entity.
UIObject, PowershellObject, DevCodeModelObject, WMIObject all are different representation to the same entity.
So say if the entity is Animal then I have AnimalUIObject, AnimalPSObject, AnimalModelObject, AnimalWMIObject, etc.
Now the implementations of AnimalUIObject, AnimalPSObject, AnimalModelObject are all in separate assemblies.
Now my scenario is I want to verify the contents of business entity Animal irrespective of the assembly it came from. So I created a GenericAnimal class to represent the Animal entity.
Now in GenericAnimal I added the following constructors:
GenericAnimal(AnimalUIObject)
GenericAnimal(AnimalPSObject)
GenericAnimal(AnimalModelObject)
Basically I made GenericAnimal depend on all the underlying assemblies so that while verifying I deal with this abstraction.
Now the other approach to do this is have GenericAnimal with an empty constructor
an allow these underlying assemblies to have a Transform() method which would build the GenericAnimal.
Both approaches have some pros and cons:
The 1st approach:
Pros: All construction logic is in one place in one class GenericAnimal
Cons: GenericAnimal class must be touched every-time there is a new representation form.
The 2nd approach:
Pros: construction responsibility is delegated to the underlying assembly.
Cons: As construction logic is spread accross assemblies, tomorrow if I need to add a property X in GenericAnimal then I have to touch all the assemblies to change the Transform method.
Which approach looks better ?
or Which would you consider a lesser evil ?
Is there any alternative way better than the above two ?
