/src/lib/design_patterns/observer.e

 1-- This file is part of a Liberty Eiffel library.
 2-- See the full copyright at the end.
 3--
 4deferred class OBSERVER[O_ -> OBSERVABLE]
 5   --
 6   -- The "Observer" Design Pattern. An Observer must be updated by an Observable (see the class OBSERVABLE in
 7   -- the lib/abilities cluster).
 8   --
 9
10feature {OBSERVABLE}
11   update (o: O_)
12         -- The observable object `o' wants Current to be updated
13      require
14         o /= Void
15      deferred
16      end
17
18end -- class OBSERVER
19--
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