Facade pattern - Example

interface General {

    public void accessGeneral();

}

interface Special extends General {

    public void accessSpecial();

}

interface Private extends General {

    public void accessPrivate();

}

class GeneralInfo implements General {

    public void accessGeneral() {

    //...

    }

    //...

}

class SpecialInfo implements Special{

    public void accessSpecial() {

        //...

    }

    public void accessGeneral() {}

      //...

}

class PrivateInfo implements Private, Special {

    public void accessPrivate() {

    // ...

    }

    public void accessSpecial() {

    //...

    }

    public void accessGeneral() {

    // ...

    }

    //...

}

class Connection {

   //...

   if (user is unauthorized) throw new Exception();

   if (user is general) return new GeneralInfo();

   if (user is special) return new SpecialInfo();

   if (user is executive) return new PrivateInfo();

   //...

}

The above code example illustrates that the whole system is not exposed to the clients. It depends on the user classification.