hi,
I am new to python and need to know why the calling of switch(1) invokes the
function "listen" twice in the below program?
import stackless
class EventHandler:
def __init__(self,*outputs):
if outputs==None:
self.outputs=[]
else:
self.outputs=list(outputs)
self.channel = stackless.channel()
stackless.tasklet(self.listen)()
def listen(self):
print "in listen()..."
while 1:
val = self.channel.receive()
self.processMessage(val)
for output in self.outputs:
self.notify(output)
def processMessage(self,val):
pass
def notify(self,output):
pass
def registerOutput(self,output):
print "in registerOutput()..."
self.outputs.append(output)
def __call__(self,val):
print "in __call__ ..."
self.channel.send(val)
class Switch(EventHandler):
def __init__(self,initialState=0,*outputs):
EventHandler.__init__(self,*outputs)
self.state = initialState
def processMessage(self,val):
print "in processMessage() of Switch..."
self.state = val
def notify(self,output):
print "in notify() of switch..."
output((self,self.state))
class Reporter(EventHandler):
def __init__(self,msg="%(sender)s send message %(value)s"):
EventHandler.__init__(self)
self.msg = msg
def processMessage(self,msg):
print "in processMessage() of Reporter..."
sender,value=msg
print self.msg % {'sender':sender,'value':value}
if __name__ == "__main__":
reporter = Reporter()
switch = Switch(0,reporter)
switch(1)
output:
=========
in __call__ ...
in listen()...
in listen()...
in processMessage() of Switch...
in notify() of switch...
in __call__ ...
in processMessage() of Reporter...
<__main__.Switch instance at 0x8d822cc> send message 1
thanks.
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