SF.net SVN: fclient: [134] trunk/sandbox/fcp/fcp_lib/events.py

[<ju...@us...>]

Revision: 134
          http://fclient.svn.sourceforge.net/fclient/?rev=134&view=rev
Author:   jurner
Date:     2008-02-04 03:49:28 -0800 (Mon, 04 Feb 2008)

Log Message:
-----------
reworked events

Modified Paths:
--------------
    trunk/sandbox/fcp/fcp_lib/events.py

Modified: trunk/sandbox/fcp/fcp_lib/events.py
===================================================================
--- trunk/sandbox/fcp/fcp_lib/events.py	2008-02-04 03:17:38 UTC (rev 133)
+++ trunk/sandbox/fcp/fcp_lib/events.py	2008-02-04 11:49:28 UTC (rev 134)
@@ -1,104 +1,63 @@
 """Signals and events"""
 
-#***********************************************************************
+#*********************************************************************
 #
-# event handler. Mostly taken from
-#http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/410686
-#
-#***********************************************************************
-class EventMeta(type):
-	"""Metaclass for events"""
-	
-	class Event(object):
-		"""Event handler
-		
-		@ivar observers: list of observers of the event
-		"""
-		
-		def __init__(self, name):
-			"""
-			@param name: (str) name of the event
-			"""
-			self.name = name
-			self.observers = []
-					
-		def __call__(self, *args, **kwargs):
-			"""Dispatches the event and additional parameters to all observers registerd"""
-			for o in self.observers: 
-				o(self, *args, **kwargs)
-		
-		def __contains__(self, observer):
-			"""Checks if an observer is aleady registered
-			@return: bool
-			"""
-			return observer in self.observers
-				
-		def __iadd__(self, observer):
-			"""Adds an observer to the event
-			@note: the observer will be called with the event as first paraeter,
-			followed by any number of *args or **kwargs passed by the caller of an event
-			"""
-			self.observers.append(observer)
-			return self
-		
-		def __isub__(self, observer):
-			"""Removes the first occurence of an observer from the event"""
-			self.observers.remove(observer)
-			return self
-			
-	def __new__(clss, name, bases, kws):
-		events = kws.get('_events_', None)
-		if events is None:
-			raise ValueError('Event classes must implement an "_event_" attribute')
-		for event_name in events:
-			kws[event_name] = clss.Event(event_name)
-		return type.__new__(clss, name, bases, kws)
-		
-
+#*********************************************************************
 class Events(object):
-	"""Base class for events
+	"""Events
 	
-	Derrived classes should list events they support in the "_events_" tuple.
-	Each event name is automagically set as attribute of the event
-	class. 
+	Class to bundle events. Usually you would add events to it by
+	adding one or more event classes as inner classes. As soon
+	as the class is instantiated the events will be auto initialized
+	and available as callable objects.
 	
-	Listeners may register to receiving events by calling __iadd__, 
-	unregister by calling __isub__ on these attributes. Callback are
-	always called with the event as first argument, followed by additional
-	arguments, depending on the event.	
+	>>> class MyEvents(Events):
+	...         class event1(Event): pass
+	...         class event2(Event): pass 
 	
-	@note: always make shure to disconnnect when event notification is no longer desired
-		
-	
-	>>> class MyEvents(Events):
-	...     _events_ = ('FooEvent', 'BarEvent')
-	... 
 	>>> events = MyEvents()
-	>>> def cb(event):
-	...     print 'Received: %s' % event.name
+	>>> sorted([event.name for event in events])
+	['event1', 'event2']
 	
-	>>> events.FooEvent += cb
-	>>> events.FooEvent()
-	Received: FooEvent
+	>>> def myCallback(event, arg): print arg
+	>>> events += (events.event1, myCallback), (events.event2, myCallback)
+	>>> events.event1('foo')
+	foo
+	>>> events.event2('bar')
+	bar
 	
-	>>> events.FooEvent -= cb
-	>>> events.FooEvent()
+	>>> events -= (events.event1, myCallback), (events.event2, myCallback)
+	>>> events.event1('foo')
 	
-	>>> events += ( (events.FooEvent, cb), (events.BarEvent, cb) )
-	>>> events.FooEvent()
-	Received: FooEvent
-	>>> events.BarEvent()
-	Received: BarEvent
+	>>> events.event1 += myCallback
+	>>> events.event1('foo')
+	foo
 	
-	>>> events -= ( (events.FooEvent, cb), (events.BarEvent, cb) )
-	>>> events.FooEvent()
+	>>> events.event1 -= myCallback
+	>>> events.event1('foo')
+		
+	@note: this class is a bit of a hack. You may not add any (not with underscore starting) 
+	attrs, methods to it except from events
+	"""
 	
-	>>> events.BarEvent()
+	def __init__(self):
+		""""""
+		for name in dir(self):
+			if not name.startswith('_'):
+				event = getattr(self, name)
+				setattr(self, name, event(name))
+		
+		
 	
-	"""
-	__metaclass__ = EventMeta	
-	_events_ = ()
-	
+	def __iter__(self):
+		"""Iterator over all events of the instance
+		@return: (L{Event}) next event in turn
+		"""
+		for name in dir(self):
+			if not name.startswith('_'):
+				event = getattr(self, name)
+				yield getattr(self, name)
+			
 	def __iadd__(self, events):
 		"""Adds one or more events / observers at once
 		@param events: tuple( (event, observer), (event, observer), ...)
@@ -114,8 +73,60 @@
 		for event, observer in events:
 			event -= observer
 		return self
+	
+#*********************************************************************
+#
+#*********************************************************************
+class Event(object):
+	"""Event class
+	
+	@ivar name: name of the event
+	@ivar observers: observers listening to the event
+	
+	>>> event = Event('myEventsName')
+	>>> event.name
+	'myEventsName'
+	
+	>>> def myCallback(event, arg): print arg
+	>>> event += myCallback
+	>>> event('foo')
+	foo
+	
+	>>> event -= myCallback
+	>>> event('foo')
+	"""
+	
+	def __init__(self, name):
+		"""
+		@param name: name of the event
+		"""
+		self.name = name
+		self.observers = []
+		
+	def __call__(self, *args, **kwargs):
+		"""Dispatches the event and additional parameters to all observers registerd"""
+		for o in self.observers: 
+			o(self, *args, **kwargs)
+		
+	def __contains__(self, observer):
+		"""Checks if an observer is aleady registered
+		@return: bool
+		"""
+		return observer in self.observers
 			
-
+	def __iadd__(self, observer):
+		"""Adds an observer to the event
+		@note: the observer will be called with the event as first paraeter,
+		followed by any number of *args or **kwargs passed by the caller of an event
+		"""
+		self.observers.append(observer)
+		return self
+	
+	def __isub__(self, observer):
+		"""Removes the first occurence of an observer from the event"""
+		self.observers.remove(observer)
+		return self
+		
 #*********************************************************************
 #
 #*********************************************************************


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