code: public NotificationChain basicSetThen(XExpression newThen, NotificationChain msgs)
  	{
  		XExpression oldThen = then;
  		then = newThen;
  		if (eNotificationRequired())
  		{
  			ENotificationImpl notification = new ENotificationImpl(this, Notification.SET, XbasePackage.XIF_EXPRESSION__THEN, oldThen, newThen);
  			if (msgs == null) msgs = notification; else msgs.add(notification);
  		}
  		return msgs;
  	}
docs: <!-- begin-user-doc -->
  <!-- end-user-doc -->
  @generated