Popular recipes tagged "subscribe"

Observer pattern implemented with Descriptor class (Python)

2012-02-14T23:43:53-08:00

Python recipe 578038 by Rodney Drenth (descriptor, observer, publish, reactive, subscribe).

The observer pattern is implemented using an observable descriptor. One creates instances of observable in a class, which allows observers to subscribe to changes in the observable. Assigning a value to the observable causes the suscribers to be notified. An observable can subscribe to another observable, in which case changes to the second propagate to subscribers of the first. The subscribe method returns a Subscription object. When this object is deleted or becomes unreferenced, the subscription is cancelled.

This version compatible with Python 3.0 Example uses unittest to help in understanding the functionality.

Threadsafe observer pattern implemented as descriptor (Python)

2010-03-13T12:17:11-08:00

Python recipe 577106 by Rodney Drenth (descriptor, observer, publish, subscribe, threads).

This is a threadsafe version of recipe 576979. A publish-subscribe (observer) pattern is implemented as a descriptor. Assigning a value notifies the observers. Uses recipe 577105 as synchlock.py and recipe 576979 as Observer.py

Observer pattern implemented with Descriptor class (Python)

2010-03-13T11:53:18-08:00

Python recipe 576979 by Rodney Drenth (descriptor, observer, publish, subscribe). Revision 5.

Flexible observer pattern implementation (Python)

2012-12-06T19:23:11-08:00

Python recipe 576962 by Glenn Eychaner (event, observer, pattern, publish, subscribe, threadsafe). Revision 16.

A simple, flexible, general-purpose observer pattern.

Observers can be callable objects or objects with a particular named method (handle_notify() by default). Events can be any object, and observers can select which events they are interested in receiving. Support for a number of different types of lightweight event objects is included.

Yet another signal/slot implementation in Python (Python)

2008-09-01T23:21:28-07:00

Python recipe 576477 by Thiago Marcos P. Santos (observer, publish, signal, slot, subscribe, weakref).

This code snippet was based on the nice recipe 439356 made by Patrick Chasco. My implementation supports only class methods callbacks. I'm keeping the idea of use weakrefs to avoid the interpreter keep the object allocated because the signal is registered (i.e. the signal object holds a reference to callback method). IMO the usage of WeakValueDictionary made the code smaller and clear and also are maintenance-free (when the object is collect by the garbage collector the signal is automatically unregistered).