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OTExample Observer

Revision as of 06:32, 23 February 2010 by Stephan.cs.tu-berlin.de (Talk | contribs) (Index.php?title=OTExample Observer moved to OTExample Observer: correct broken title (included URL part))

This is a reusable implementation of the omnipresent design pattern "Observer".

Note, that a well designed program in Object Teams will usually not require an explicit Observer infrastructure. See the Stopwatch example for an example, how a plain callin-binding suffices.

This demo should, however, give a quick understanding to some techniques of Object Teams for all who are familiar with the Observer pattern (the OTDT ships with a simpler version of this pattern).

protocol/
ObserverPattern
This implements the GoF pattern very straight forwardly.

Open spots are:

  • method Subject.changeOp which should be triggered at relevant base-level events
  • and the abstract method Observer.update() which should realize the Observer's reaction.
flower_example/
Bee
Hummingbird
Flower
Implement some base entities
flower_example/
ObservingOpen
ObservingClose
Two applications of the Observer pattern binding the above open spots using callin and callout bindings.
flower_example/
Main
A simple main program

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