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Java Java Objects Harnessing the Power of Objects Throwing Exceptions

Carlos Salcedo
Carlos Salcedo
1,788 Points
Posted by Carlos Salcedo
Carlos Salcedo
1,788 Points

trouble calling the exception

i think i might be doing it wrong by the way i constructed the method in the first place and by the way i am going about of throwing the exception.

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;
    try{
      GoKart.drive(400);
    }catch (IllegalArgumentException iae){
      System.out.printf("the error was %s ", iae.getMessage());
    }

  }
}
Chris Tvedt
Chris Tvedt
3,795 Points
Chris Tvedt
Chris Tvedt
3,795 Points

What errors are you getting?

Carlos Salcedo
Carlos Salcedo
1,788 Points
Carlos Salcedo
Carlos Salcedo
1,788 Points

im getting this error-... Bummer! Make sure you throw a new IllegalArgumentException if the requested amount of laps would make the battery less than zero.

1 Answer

Alexander La Bianca
Alexander La Bianca
15,959 Points

Carlos, See below how you should implement this method. What you did in your code is considered handling the exception, but you need a method that throws an exception before you can handle it. Also see how you can you try catch blocks to then call the public drive method. 

public void drive(int laps) throws IllegalArgumentException {
    if(barCount < laps) {
        throw new IllegalArgumentException();
    }
    lapsDriven += laps;
    barCount -= laps;


}

//Lets instantiate a GoKart object
GoKart someKart = new GoKart("Red");
//Lets try to drive it around laps
try {
     someKart.drive(10);                                    //Drive 10 laps
}
catch(IllegalArgumentException exc) {          //This exception is raised if the kart has less than 10 bars
     System.println(exc.getMessage());
}

Keep in mind that in java, a method that throws an exception like the drive method NEEDS to be handled at some point when it is called

Carlos Salcedo
Carlos Salcedo
1,788 Points
Carlos Salcedo
Carlos Salcedo
1,788 Points

exactly what i needed thanks alot for the tip