# dispatch.py
# definitions:
import threading
class Dispatcher(object):
def __init__(self, targets=None, nonBlocking=True):
if not targets or targets is None:
self._targets = []
else:
self._targets = targets
self._nonBlocking = nonBlocking
def __iadd__(self, target):
self._targets.append(target)
return self
def __isub__(self, target):
self._targets.remove(target)
return self
def isNonBlocking(self):
return self._nonBlocking
nonBlocking = property(isNonBlocking)
def __call__(self, *listArgs, **kwArgs):
def invokeTargets():
for target in self._targets:
target(*listArgs, **kwArgs)
if self.nonBlocking:
threading.Timer(0, invokeTargets).start()
else:
invokeTargets()
# demos:
def Test1():
"""
A simple example demonstrating most functionality.
"""
def m1():
print 'm1 invoked'
def m2():
print 'm2 invoked'
e = Dispatcher()
e += m1
e += m2
e += m2
print 'Dispatching:'
e()
e -= m1
print 'Dispatching:'
e()
e -= m2
print 'Dispatching:'
e()
def Test2():
"""
A more realistic example for the OO programmer.
"""
class Sprite(object):
def __init__(self, location):
self._location = location
locationChanged = Dispatcher()
def getLocation(self):
return self._location
def setLocation(self, newLocation):
oldLocation = self._location
self._location = newLocation
# Dispatch a "property change event"
self.locationChanged(oldLocation, newLocation)
location = property(getLocation, setLocation)
s = Sprite((2,4))
def SpriteLocationChanged(oldLocation, newLocation):
print 'oldLocation =', oldLocation
print 'newLocation =', newLocation
s.locationChanged += SpriteLocationChanged
s.location = (3,4)
s.location = (4,4)
if __name__ == '__main__':
Test1()
Test2()
