public DOMMessage handle(DOMMessage message) {
                        boolean result
                            = (message instanceof MonarchActionMessage)
                                ? ((MonarchActionMessage)message).getResult()
                                : false;
                        if (result) {
                            ChangeSet cs = new ChangeSet();
                            serverPlayer.csAddMercenaries(mercenaries,
                                                          mercPrice, cs);
                            sendElement(serverPlayer, cs);
                        }
                        return null;
                    }