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Java Java Objects Harnessing the Power of Objects Throwing Exceptions

How to solve this challenge

How to solve this challenge

GoKart.java
class GoKart {
  public static final int MAX_BARS = 8;
  private String color;
  private int barCount;
  private int lapsDriven;

  public GoKart(String color) {
    this.color = color;
  }

  public String getColor() {
    return color;
  }
  public void charge() {
    barCount = MAX_BARS;
  }

  public boolean isBatteryEmpty() {
    return barCount == 0;
  }

  public boolean isFullyCharged() {
    return MAX_BARS == barCount;
  }

  public void drive() {
    drive(1);
  }

  public void drive(int laps) {
    lapsDriven += laps;
    barCount -= laps;
    if (laps>barCount){
      throw new IllegalArgumentException("there are not enough bars to support request");
    }
     lapsDriven += laps;
    barCount -= laps;
  }
}

1 Answer

Jennifer Nordell
seal-mask
STAFF
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there! You're doing really well, but you have some repeated code in that drive method. Take a look at the Bummer! message:

Bummer! Make sure you throw the exception before you change the barCount and lapsDriven fields.

We first want to make sure we're not asking for something impossible. If our car has 2 energy bars left and we ask it to drive 5 laps, that should not work. It's there we want to throw the exception. Only if an exception doesn't get thrown do we want to increase the lapsDriven and decrease the barCount.

Removing the 2 lines before your if statement causes this to pass the challenge.

Hope this helps! :sparkles: