Behavioral Design Patterns The Observer Pattern Roberto Demontis Sylvain Giroux.
Design Pattern - 2. Observer
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Transcript of Design Pattern - 2. Observer
PRESENTATION NAME
Observer Pattern
Company Name
Observer
Problem:We have to change values through methods in a class
Update observer from Subject Object
Observer from Subject Object
Class Diagram Observer
Final Diagram
Interfaces Observer
// interfaccia subject per i metodi di registrazione, cancellazione e notifica di un objserverPublic interface Subject{
public void registererObserver(Observer o);public void removeObserver(Observer o);public void notifyObserver();}// interfaccia con metodo specifico dell'observer per update degli observer
Public interface Observer{public void update(float temp);} // interfaccia con metodo display per la visualizzazione Public interface DisplayElement{public void display();}
Subject
implementation
Observer implementation
Subject
implementation
with java built-in
Observer implementation with java built-in