Python decorators with classes

class_decorators.py

class WithoutParams(object):
    def __init__(self, func):
        """
        Constructor receives target function.
        """
        self.func = func

    def __call__(self, *args, **kwargs):
        """
        Arguments intended for target function are passed to __call__.
        From here you can call the target any way you see fit.
        """
        self.func("Never gonna give you up")


class WithParams(object):
    def __init__(self, val):
        """
        Constructor takes decorator params instead of target.
        """
        self.val = val

    def __call__(self, func):
        """
        Target function is passed in here instead.
        This is where we create a wrapper function to replace the target.
        """
        def wrapped(*args, **kwargs):
            """
            Wrapper function takes the target arguments and calls target.
            """
            func(self.val)

        return wrapped

@WithoutParams
def a(text):
    print text

@WithParams("Never gonna let you down")
def b(text):
    print text

if __name__ == "__main__":
    a("hello world")
    b("foo bar")