Converging Multiple Classes

Jean-Michel Pichavant jeanmichel at sequans.com
Fri Feb 4 18:07:39 CET 2011


Wanderer wrote:
> I have a bunch of cameras I want to run tests on. They each have
> different drivers and interfaces. What I want to do is create python
> wrappers so that they all have a common interface and can be called by
> the same python test bench program. I'm not sure what to call it. I
> don't think it's inheritance. Maybe there is no official thing here
> and I just need to brute force my way through it. Is there some
> programming methodology I should be using?
>
> Thanks
>   
I guess Interface/Abstract classes are what you are searching for.

# Camera is the interface/abstract base class of all cameras.
# it defines all the function that a Camera needs to implement.
class Camera(object):
    def printCameraType(self):
       # This code is common to all Cameras
       print self.__class__.__name__

    def shutdown(self):
       # an abstract method raises NotImplementedError and does not 
implement anything
       # however it indicates to all child classes what they need to 
implement.
       raise NotImplementedError()

# One implementation of a Camera
class ATypeOfCamera(Camera):
    def shutdown():
       print 'I am implementing the shutdown for that very specific 
Camera type'
       return 0

class AnotherTypeOfCamera(Camera):
    def shutdown():
       print 'Shutting down with the proper implementation'
       return 0


Now here is what you test bench whould look like:

from camera import ATypeOfCamera, AnotherTypeOfCamera

for cameraType in [ATypeOfCamera, AnotherTypeOfCamera]:
    myCam = cameraType()
    myCam.printCameraType()
    myCam.shutdown()

JM



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