[Update 2014-02-02: I’ve posted a video showing a visualization of this pattern at http://www.youtube.com/watch?v=WEXh1WoppMU] In a loosely-coupled system connected with asynchronous messages, a flood of client requests can exceed the capacity of a service. When this happens, we would prefer that the service respond with an indication of the overloaded condition, rather than making us […]
22
May
2011
Actors Make Better Observers
Tags: actor, asynchronous, blocking, distribution, JavaScript, listener, message-passing, observer, patterns, pub-sub, synchronous
The Observer pattern causes temporal coupling in systems with synchronous message passing. This can lead to failure in Object-Oriented systems. Asynchronous messaging avoids the pitfalls. Actor-based implementations more accurately realize the original intent of the pattern. The intent of the Observer pattern is to “define a one-to-many dependency between objects so that when one object […]