when adding callbacks, the code may not be very focused on the actual problem. A solution si to write a generic base class to deal with the callbacks issues, and then decorate the methods with the event for wich you want a binding.
Python, 54 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | class CallbackBase:
def __init__(self):
self.__callbackMap = {}
for k in (getattr(self, x) for x in dir(self)):
if hasattr(k, "bind_to_event"):
self.__callbackMap.setdefault(k.bind_to_event, []).append(k)
elif hasattr(k, "bind_to_event_list"):
for j in k.bind_to_event_list:
self.__callbackMap.setdefault(j, []).append(k)
## staticmethod is only used to create a namespace
@staticmethod
def callback(event):
def f(g, ev = event):
g.bind_to_event = ev
return g
return f
@staticmethod
def callbacklist(eventlist):
def f(g, evl = eventlist):
g.bind_to_event_list = evl
return g
return f
def dispatch(self, event):
l = self.__callbackMap[event]
f = lambda *args, **kargs: \
map(lambda x: x(*args, **kargs), l)
return f
## Sample
class MyClass(CallbackBase):
EVENT1 = 1
EVENT2 = 2
@CallbackBase.callback(EVENT1)
def handler1(self, param = None):
print "handler1 with param: %s" % str(param)
return None
@CallbackBase.callbacklist([EVENT1, EVENT2])
def handler2(self, param = None):
print "handler2 with param: %s" % str(param)
return None
def run(self, event, param = None):
self.dispatch(event)(param)
if __name__ == "__main__":
a = MyClass()
a.run(MyClass.EVENT1, 'mandarina')
a.run(MyClass.EVENT2, 'naranja')
|
Here is a sample class which has two events: EVENT1 and EVENT2, and we have 2 handlers, handler1 is register to EVENT1 and handler2 will be called either for EVENT1 or EVENT2. The run method is MyClass's main loop, and will dispatch event for the corresponding event. This will return a function, and we can pass the arguments we wanto to the function. A list with all the returned value will be return
Maybe, a more elegant solution can be implement using Metaclasses
Tags: oop
