Index: VerpakkingsDefinitie/ApplicationContext.pas
===================================================================
diff -u -r551 -r555
--- VerpakkingsDefinitie/ApplicationContext.pas	(.../ApplicationContext.pas)	(revision 551)
+++ VerpakkingsDefinitie/ApplicationContext.pas	(.../ApplicationContext.pas)	(revision 555)
@@ -7,11 +7,14 @@
 
 interface
 
+uses
+  ObserverPattern;
+
 // SUB CONTEXTS: klassen die overeenkomen met bepaalde sub-context (bv. alles gerelateerd met authenticatie).
 
 // - UserServerService
 type
-  TUserServerServiceContext = class
+  TUserServerServiceContext = class(TSubject)
   private
     FSessionKey: string;
     FGebruikersNaam: string;
@@ -20,6 +23,7 @@
     FErrorMessage: string;
     FInternalErrorMessage: string;
   public
+    procedure Changed();
     property SessionKey: string read FSessionKey write FSessionKey;
     property GebruikersNaam: string read FGebruikersNaam write FGebruikersNaam;
     property IsOK: Boolean read FIsOK write FIsOK;
@@ -31,14 +35,19 @@
   // Application context bevat alle sub-contexts
   TApplicationContext = class
   private
-      FUserServerServiceContext: TUserServerServiceContext;
+    FUserServerServiceContext: TUserServerServiceContext;
   public
     constructor Create();
     property UserServerServiceContext: TUserServerServiceContext read FUserServerServiceContext write FUserServerServiceContext;
   end;
 
 implementation
 
+procedure TUserServerServiceContext.Changed();
+begin
+  self.Change();
+end;
+
 constructor TApplicationContext.Create();
 begin
   FUserServerServiceContext := TUserServerServiceContext.Create();