&& (t.isReady())
&& (t.isUpgradable())
&& (!t.getGrid().isOccupied())
&& (getCredits() >= t.getType().getNext().getPrice())) {
UpgradeTowerMessage utm = new UpgradeTowerMessage();
utm.setClientId(getPlayerId());
utm.setTowerId(t.getId());
getNetwork().sendMessage(utm);
setCredits(getCredits() - t.getType().getNext().getPrice());
this.fireSelectedChangedEvent("upgrade");
t.getGrid().setOccupiedStatus(true);
return true;