ghubstan cffbfcf481
Split API examples & doc generator into separate modules
This might give Python devs an easier time than if all the sample
code lived deep inside a gradle project.  This means there is
no root project gradle build file;  the reference-doc-builder and
java-examples modules are separate java projects, with their own
build files.
2022-03-16 17:21:25 -03:00

66 lines
1.9 KiB
Python

# From https://expobrain.net/2010/07/31/simple-event-dispatcher-in-python
class EventDispatcher(object):
"""
Generic event dispatcher which listen and dispatch events
"""
def __init__(self):
self._events = dict()
def __del__(self):
"""
Remove all listener references at destruction time
"""
self._events = None
def has_listener(self, event_type, listener):
"""
Return true if listener is register to event_type
"""
# Check for event type and for the listener
if event_type in self._events.keys():
return listener in self._events[event_type]
else:
return False
def dispatch_event(self, event):
"""
Dispatch an instance of Event class
"""
# Dispatch the event to all the associated listeners
if event.type in self._events.keys():
listeners = self._events[event.type]
for listener in listeners:
listener(event)
def add_event_listener(self, event_type, listener):
"""
Add an event listener for an event type
"""
# Add listener to the event type
if not self.has_listener(event_type, listener):
listeners = self._events.get(event_type, [])
listeners.append(listener)
self._events[event_type] = listeners
def remove_event_listener(self, event_type, listener):
"""
Remove event listener.
"""
# Remove the listener from the event type
if self.has_listener(event_type, listener):
listeners = self._events[event_type]
if len(listeners) == 1:
# Only this listener remains so remove the key
del self._events[event_type]
else:
# Update listeners chain
listeners.remove(listener)
self._events[event_type] = listeners