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

Posted by anthony fontes
anthony fontes
12,405 Points

I'm stumped on the "throwing exceptions" code challenge

keeps saying "Are you sure you threw the IllegalArgumentException if the requested amount of laps would make the battery less than zero?"

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);
  }

  public void drive(int laps) {
    // Other driving code omitted for clarity purposes
   int newLap = mBarsCount + laps;
    if (newLap > MAX_BARS) {
      throw new  IllegalArgumentException("Not enough battery remains");
    }
    mBarsCount = newLap;
  }

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

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

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

}

1 Answer

jcorum
jcorum
71,830 Points

anthony, no need for a new variable newLap. First check to see if the current count (mBarsCount) minus the laps being passed into the function is less than 0. If not, throw the exception. Otherwise, subtract laps from mBarCount:

  public void drive(int laps) {
    // Other driving code omitted for clarity purposes
    if (mBarsCount - laps < 0) {
      throw new IllegalArgumentException();
    } else {
      mBarsCount -= laps;
    }
  }
anthony fontes
anthony fontes
12,405 Points

Thanks! that helped