libutilitaspy.patterns.observer
This module implements the base classes of the observer pattern [GoF94].
[GoF94] |
- Gamma, R. Helm, R. Johnson and J. Vlissides. Design Patterns: Elements of reusable Object-Oriented Software. 1994
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class libutilitaspy.patterns.observer.Observer[source]
An observer (also called listener) is any object which can be registered
with some Observable object to be notified whenever the
Observable object is updated.
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notify(*args, **kwargs)[source]
Method executed whenever any Observable where self is registered is updated.
It should be overriden by a subclass.
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class libutilitaspy.patterns.observer.Observable[source]
An observable object is any object that has a list of registered
Observer objects which are notified whenever the observable object is
updated (a relevant change of state occurs).
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register(observer)[source]
Registers the observer object.
Parameters: | observer (Observer) – The object to register. |
Post : | after(self.observers) == before(self.observers) + [observer] |
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deregister(observer)[source]
Unregisters the observer object.
Parameters: | observer (Observer) – The object to register. |
Pre : | observer in self.observers |
Post : | after(self.observers) == before(self.observers) - [observer] |
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update(*args, **kwargs)[source]
Notifies all registered observers.