private void checkErrors() {
        if(!"".equals(heightError.getText()) || !"".equals(widthError.getText()) || !"".equals(lengthError.getText()) ||
           !"".equals(quantityError.getText()) || !"".equals(colourPrintError.getText()) || !"".equals(gradeError.getText()))
        {
            
        }
        else
        {
            //check if the type of box can be supplied
            if(canBeSupplied())
            {
                placeOrder(); // place the order and display the total cost
                resetFields(); // reset the fields before a new order
                boxTypesInit(); // we have to re-initialise the box types because we modified the card grade of a box type when we created the box so that it had only one value in the array
                
            }
            else
            {
                setTypeError("This type of box cannot be supplied ! Please try another configuration !");
            }
        }
    }