public StackRequest getAvailableRequest(int i) {
if (requests.getStackInSlot(i) == null) {
return null;
} else if (isFulfilled(i)) {
return null;
} else if (RobotRegistry.getRegistry(worldObj).isTaken(new ResourceIdRequest(this, i))) {
return null;
} else {
StackRequest r = new StackRequest();
r.index = i;