Add partial correction of ex. 7

src/main/java/fr/unantes/l3/construction/exercice6/ReferenceToAction.java

@@ -31,15 +31,19 @@ public class ReferenceToAction {
 
     public void unSet() {
         if (action.isPresent()) {
-            action.get().button().basicUnset();
+            opposite(action.get()).basicUnset();
             this.basicUnset();
         }
     }
 
+    private ReferenceToButton opposite(Action action) {
+        return action.button();
+    }
+
     public void set(Action action) {
 
         this.basicSet(action);
-        action.button().basicSet(this.container);
+        opposite(action).basicSet(this.container);
     }
 
     public Action get() {

src/main/java/fr/unantes/l3/construction/exercice7/Action.java

+package fr.unantes.l3.construction.exercice7;
+
+public class Action {
+}

src/main/java/fr/unantes/l3/construction/exercice7/Button.java

+package fr.unantes.l3.construction.exercice7;
+
+public class Button {
+}

src/main/java/fr/unantes/l3/construction/exercice7/ReferenceToOne.java

+package fr.unantes.l3.construction.exercice7;
+
+import java.util.Optional;
+
+public class ReferenceToOne<C, T> {
+
+    private final C container;
+    private Optional<T> target = Optional.empty();
+
+    public ReferenceToOne(C container) {
+        this.container = container;
+    }
+
+    public boolean isSet() {
+        return target.isPresent();
+    }
+
+    public void basicSet(T newTarget) {
+        if (this.isSet()) {
+            this.unSet();
+        } else {
+            this.target = Optional.of(newTarget);
+        }
+    }
+
+    public void basicUnset() {
+        if (target.isPresent()) {
+            target = Optional.empty();
+        }
+    }
+
+    public void unSet() {
+        if (target.isPresent()) {
+            opposite(target.get()).basicUnset();
+            this.basicUnset();
+        }
+    }
+
+    private ReferenceToOne<T, C> opposite(T target) {
+        return null;
+        //return target.button();
+    }
+
+    public void set(T newTarget) {
+        this.basicSet(newTarget);
+        opposite(newTarget).basicSet(this.container);
+    }
+
+    public T get() {
+        return target.get();
+    }
+}