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Java Java Objects Harnessing the Power of Objects Throwing Exceptions

Posted by Osman Mukhwana
Osman Mukhwana
Courses Plus Student 488 Points

Exceptions

I need assistance throwing in an IllegalArgumentException in my drive method, if the lap request will make the battery less than zero. Thanks in advance.

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 > MAX_BARS){
    throw new IllegalArgumentException ("Too many laps!!");
    }
  }
}
Tai Do
Tai Do
2,312 Points

try this instead: public void drive(int laps) {

if (laps > barCount) {

  throw new IllegalArgumentException("Not enough battery!!");

}

lapsDriven += laps;

barCount -= laps;

}

Basically, instead of MAX_BARS, you use barCount. We aren't using MAX_BARS because we can not assume that the kart is fully charged.

HOPE THIS HELPS!!!!!

3 Answers

Tai Do
Tai Do
2,312 Points

Did my response help you?

Osman Mukhwana
Osman Mukhwana
Courses Plus Student 488 Points

Hi Tai Do. Yes your answer was very helpful. Thank you. I couldn't find a place rate or comment on your response though.

james south
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
james south
Front End Web Development Techdegree Graduate 33,271 Points
james south
.a{fill-rule:evenodd;}techdegree seal-36
james south
Front End Web Development Techdegree Graduate 33,271 Points

consider very carefully what they are asking for, what should throw the exception? then you need to check for the error condition before modifying the two variables.

Osman Mukhwana
Osman Mukhwana
Courses Plus Student 488 Points

Thank you.

Joshua Tiedtke
Joshua Tiedtke
5,647 Points
Joshua Tiedtke
Joshua Tiedtke
5,647 Points

I can't explain to you why it doesn't work as i'm just a beginner myself and tried the exact same thing as you, but using '<' instead of '>' worked for me. Also you have to write the illegal argument before: lapsDriven += laps; barCount -= laps;

I hope it helps finishing the task but I really would like to know the 'why?' behind it because I finished the task more with experimenting then really understanding it.

Osman Mukhwana
Osman Mukhwana
Courses Plus Student 488 Points

Appreciated