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Java Java Objects Delivering the MVP Applying a Discount Code

olu adesina
olu adesina
23,007 Points

use of regEx for validation task

Hi guys

i decided to use regular expression for this task which i have tested and run and it seems to work fine in another ide

but it keeps telling me its wrong. is it wrong please have a look thanks

Order.java
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Order {
  private String itemName;
  private int priceInCents;
  private String discountCode;

  public Order(String itemName, int priceInCents) {
    this.itemName = itemName;
    this.priceInCents = priceInCents;
  }

  public String getItemName() {
    return itemName;
  }

  public int getPriceInCents() {
    return priceInCents;
  }

  public String getDiscountCode() {
    return discountCode;
  }

  public void applyDiscountCode(String discountCode) {
    this.discountCode = normalizeDiscountCode(discountCode);
  }

   private String normalizeDiscountCode(String code){

      String pattern = "^[a-zA-Z$]+$";

      // Create a Pattern object
      Pattern r = Pattern.compile(pattern);

      // Now create matcher object.

    try{
      Matcher m = r.matcher(code);

    if (!m.find( )) {
         throw new IllegalArgumentException("Invalid discount code");
      }
      else{
          return code.toUpperCase();
      }
    }
    catch(IllegalArgumentException iae){

      System.out.println(iae.getMessage());
    }

       return "No code found";

  }
}
Example.java
public class Example {

  public static void main(String[] args) {
    // This is here just for example use cases.

    Order order = new Order(
            "Yoda PEZ Dispenser",
            600);

    // These are valid.  They are letters and the $ character only
    order.applyDiscountCode("abc");
    order.getDiscountCode(); // ABC

    order.applyDiscountCode("$ale");
    order.getDiscountCode(); // $ALE


    try {
      // This will throw an exception because it contains numbers
      order.applyDiscountCode("ABC123");
    } catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    }
    try {
      // This will throw as well, because it contains a symbol.
      order.applyDiscountCode("w@w");
    }catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    }

  }
}

1 Answer

Brendan Whiting
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Brendan Whiting
Front End Web Development Techdegree Graduate 84,738 Points

In your normalizeDiscountCode method, you're correctly throwing the IllegalArgumentException, but then you're also catching the error in the same method and printing it out.

What they want you to do is throw the error in normalizeDiscountCode and not catch the error, which will pass the error up to whichever method called it. Take a look at Example.java, which is where the code is being used. They're calling the applyDiscountCode method, which in turn calls normalizeDiscountCode. They have some of them wrapped in try/catch. If normalizeDiscountCode throws an error, it should bubble up to here where they're catching the error. But you're catching the error down inside the method and then the error has been handled, it's gone. They want it to be handled upstream.