def addListener[T <: ActionListener](listener: T) {

    if (listener.isInstanceOf[EntityClickListener])
      entityInteractionListeners.add(listener.asInstanceOf[EntityClickListener])

    if (listener.isInstanceOf[ButtonPressedListener])
      buttonPressedListeners.add(listener.asInstanceOf[ButtonPressedListener])

    if (listener.isInstanceOf[ItemClickListener])
      itemClickListeners.add(listener.asInstanceOf[ItemClickListener])

    if (listener.isInstanceOf[ItemOptionListener])
      itemOptionListeners.add(listener.asInstanceOf[ItemOptionListener])

    if (listener.isInstanceOf[ItemOnObjectListener])
      itemOnObjectListeners.add(listener.asInstanceOf[ItemOnObjectListener])

    if (listener.isInstanceOf[GroundItemClickListener])
      groundItemListeners.add(listener.asInstanceOf[GroundItemClickListener])

    if (listener.isInstanceOf[ItemOnGroundItemListener])
      itemOnGroundItemListeners.add(listener.asInstanceOf[ItemOnGroundItemListener])

    if (listener.isInstanceOf[ItemOnItemListener])
      itemOnItemListeners.add(listener.asInstanceOf[ItemOnItemListener])

    if (listener.isInstanceOf[ObjectClickListener])
      objectClickListeners.add(listener.asInstanceOf[ObjectClickListener])
  }