metaclass.py

class ComposedLocator(object):
    """
    A responder locator that consists of other locators.
    """
    interface.implements(amp.IResponderLocator)

    class __metaclass__(type):
        def __new__(meta, name, bases, attrs):
            """
            Makes sure every subclass gets its own set of locator classes.
            """
            attrs["_locatorClasses"] = []
            return type.__new__(meta, name, bases, attrs)


    def __init__(self, *args, **kwargs):
        self._locators = [l(*args, **kwargs) for l in self._locatorClasses]


    def locateResponder(self, name):
        """
        Locates a responder from all the component responders.
        """
        for locator in self._locators:
            responder = locator.locateResponder(name)
            if responder is not None:
                return responder


    @classmethod
    def component(cls, locatorClass):
        """
        Registers a component locator.
        """
        cls._locatorClasses.append(locatorClass)
        return locatorClass