Ajout Observer class

src/java/main/fr/univlille/iut/r304/cpt/Observer.java

+package fr.univlille.iut.r304.cpt;
+
+public interface Observer {
+    public void update(Subject subject);
+    public void update(Subject subject, Object obj);
+}

src/java/main/fr/univlille/iut/r304/cpt/Subject.java

@@ -11,12 +11,12 @@ public abstract class Subject {
     public void detach(Observer observer){
         observers.remove(observer);
     }
-    protected notifyObservers(){
+    protected void notifyObservers(){
         for(Observer observer : observers){
             observer.update();
         }
     }
-    protected notifyObservers(Object obj){
+    protected void notifyObservers(Object obj){
         for(Observer observer : observers){
             observer.update(obj);
         }