def __del__(self):
if not sip.isdeleted(self):
for obs in self.observed():
# Notify of the subscribed Observables that they have a None
# reference
if obs is not None: obs._checkRefs()
Node.__del__(self)
def __init__(self, react=None, hz=None, parent=None):
""":class:`Observer` objects can be subscribed to many
:class:`Observable` instances in order to listen to their
notifications. The argument *react* can be set to the handler
function (it must accept one argument) that will be called as
consequence of an observable notification. If *react* is None,
the member method :meth:`_react` will be called. *hz* defines
the rate at which the observer will react to
notifications. Available values are:
* None --- immediately;
* 0 --- never;
* <float> --- at the selected frequency (in hz).
*parent* defines the observers parent.
.. note:: The list of the subscribed observables is composed
by weak references, so it is necessary to keep both
observables and observers alive.
"""
if not sip.ispycreated(self):
QtCore.QObject.__init__(self, parent)
Node.__init__(self)
self._internal = self._InternalQObject()
self.__observed = set()
self.__queue = set()
self.__timer = QtCore.QTimer(timeout=self._update)
self.__hz = None if hz is None else float(hz)
if self.__hz: self.__timer.start(1000/float(hz))
self.__react = assertIsInstance(react, None, collections.Callable)
def __del__(self):
if not sip.isdeleted(self):
generator = ((ref(), record) for (ref, record) \
in self.__observers.items() if ref() is not None)
for obs, record in generator:
# Notify the subscribed observers they have a None reference.
record.trigger.disconnect(obs._reactSlot)
obs._checkRefs()
# To make sure that the children's '__del__' method is invoked.
for child in tuple(self.children()):
child.setParent(None)
Node.__del__(self)
def __init__(self, parent=None):
""":class:`Observable` objects can be subscribed by a list of
:class:`Observer` instances. An Observable can trigger all or only
a subset of the subscribed observers by invoking the method
:meth:`trigger`. The attribute *parent* defines the parent object
of the observable.
.. note:: The list of the subscribed observers is composed by weak
references, so it is necessary to keep both observables and
observers alive.
"""
QtCore.QObject.__init__(self, parent)
Node.__init__(self)
self.__observers = dict()
