Question

my code is to read lines from a .txt and parse those inputs.

inputs are in this form <operation> <category> <name> <price> <quantity> <weight> <optional field1> <optional field2>

Electronics have 2 option fields is it fragile (F/NF) and the state it’s shipping to, groceries have 1 optional field perishable (P/NP). here’s a few example of line inputs

insert clothing shirt 20.50 1 1

insert electronics PS3 300 1 5.2 F NM

insert groceries cabbage 2.00 5 1 NP

Im thinking of writing a legalLine() method to process the errors in inputs

class sampleClass{
          public static void isLegalLine(String lineInput){
    Scanner s = new Scanner(lineInput);
    String operation = null;
    String category = null;
    String name = null;
    float price = 0;
    int quantity = 0;
    float weight = 0;
    String opt1 = null;
    String opt2 = null;
    try{
        operation = s.next(); 
        category = s.next();
        name = s.next();
        price = Float.parseFloat(s.next());
        quantity = Integer.parseInt(s.next());
        weight = Float.parseFloat(s.next());
        if (!operation.equalsIgnoreCase("insert")
                && !operation.equalsIgnoreCase("search")
                && !operation.equalsIgnoreCase("delete")
                && !operation.equalsIgnoreCase("update")
                && !operation.equalsIgnoreCase("print")) {
            System.out.println("invalid operation");
        }
        // more validations for variables category, name, price, quantity, weight goes here
        if(category.equalsIgnoreCase("electronics")){
            try{
                opt1 = s.next();
                opt1 = s.next();
            }catch(Exception e){

            }
        }else if(category.equalsIgnoreCase("groceries")){
            opt1 = s.next();
        }
    }catch (Exception e){
        //general catch for now
        e.getMessage();
    }
}


          public static void main(String[] args) 
      {
               FileReader freader = new FileReader(args[0]);
               BufferedReader bfrReader = new BufferedReader(freader);
               isLegalLine(bfrReader.readLine());


                //program does calculation for total price of input
}

you see… I’ve gone through all the trouble setting each token to its respective variables in the isLegalLine(), how can I pass those information back to the main()? and is this a good design for processing input line errors?

Answer 1

Since you will need to process them as well, a good solution I see is this:

Create a Product class with three subclasses: clothing, electronics, and groceries

Then make your function

public static Product isLegalLine(String lineInput)

return the Product after parsing the line.