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Java Java Objects (Retired) Harnessing the Power of Objects Throwing Exceptions

Posted by Ahmed Alfatih
Ahmed Alfatih
Courses Plus Student 598 Points

what is wrong with

Line 15 to 17

GoKart.java 
public class GoKart {
  public static final int MAX_BARS = 8;
  private String mColor;
  private int mBarsCount;

  public GoKart(String color) {
    mColor = color;
    mBarsCount = 0;
  }

  public String getColor() {
    return mColor;
  }

  public void drive() {
    drive(1);
    throw new IllegalArgumentException ("Not enough bttery remains");
  }

  public void drive(int laps) {
    // Other driving code omitted for clarity purposes
    mBarsCount -= laps;
  }

  public void charge() {
    while (!isFullyCharged()) {
      mBarsCount++;
    }
  }

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

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

}

1 Answer

Derek Markman
Derek Markman
16,291 Points

In your overloaded 'drive' method (The drive method that takes an int as an argument). You need to check if mBarsCount is less than the number of laps passed into the drive method. If the number of laps is greater than mBarsCount, then you need to throw an IllegalArgumentException that says "Not enough battery remains."

Since you're trying to throw an IllegalArgumentException from your drive method if mBarsCount is less than the number of laps, you need to specify on your method that it throws an IllegalArgumentException.

public class GoKart {
  public static final int MAX_BARS = 8;
  private String mColor;
  private int mBarsCount;

  public GoKart(String color) {
    mColor = color;
    mBarsCount = 0;
  }

  public String getColor() {
    return mColor;
  }

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

//modify the overloaded drive method
  public void drive(int laps) throws IllegalArgumentException { //specifies that this method could throw an IllegalArgumentException

    // Other driving code omitted for clarity purposes
    if(mBarsCount < laps) { //checks if mBarsCount is less than the number of laps

      throw new IllegalArgumentException("Not enough battery remains.");  //throws an IllegalArgumentException, with the message you specified.
    }
    mBarsCount -= laps;  
  }

  public void charge() {
    while (!isFullyCharged()) {
      mBarsCount++;
    }
  }

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

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

}

Let me know if you have any other questions.

Ahmed Alfatih
Ahmed Alfatih
Courses Plus Student 598 Points

Thanks alot

Derek Markman
Derek Markman
16,291 Points

No problem. Also, Ahmed Alfatih , if my answer has helped you out it would be much appreciated if you gave it an upvote. Thanks :)