if ((inventory - quantity) >= 0) {
int newInventory = inventory - quantity;
requestedBook.setInventory(newInventory);
} else {
throw new OrderException(
"Not enough of " + bookId
+ " in stock to complete order.");
}
}
} catch (Exception ex) {
throw new OrderException(
"Couldn't purchase book: " + bookId + ex.getMessage());
}
}