Apples and Oranges with an zope component adapter

apples_oranges_adapter.py

from zope.component import getGlobalSiteManager, adapts
from zope.interface import Interface, implements

class IApple(Interface):
    """I'm an apple"""

class Apple:
    implements(IApple) # we need this so we can adapt this class

    worm = "~~~"

class Orange:
    def slices(self):
        return [1, 2, 3]

class ISlicedApple(Interface):
    """interface of the adapted apple"""
    def slices():
        """ Return slices """

class SlicedApple:
    """"""
    implements(ISlicedApple)#same as for utility
    adapts(IApple)#the interface which we augment

    def __init__(self, apple):
        self.apple = apple#setting up the adaptee

    def slices(self):
        self.apple.worm = None #remove the worm
        return [1, 2, 3, 4]

def get_slices(basket):
    """For each item in the basket get it's slices"""
    slices = []
    for item in basket:
        slices.append(item.slices())
    return slices

if __name__ == '__main__':
    gsm = getGlobalSiteManager()
    #Same as the utility
    gsm.registerAdapter(SlicedApple)
    
    #Now that we can get our adapted apple. 
    #Notice that we query using the interface and not the implementation SlicedApple
    adapted_apple = gsm.getAdapter(Apple(), ISlicedApple)

    basket = []
    basket.append(Orange())
    basket.append(adapted_apple)
    print get_slices(basket)