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

Posted by Admire Dhodho
Admire Dhodho
5,411 Points

Okay, so let's throw an IllegalArgumentException from the drive method if the requested number of laps cannot be complet

Okay, so let's throw an IllegalArgumentException from the drive method if the requested number of laps cannot be completed on the current battery level. Make the exception message "Not enough battery remains" pliz help?

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  newLaps = mBarsCount - laps;
    if ( newLaps > MAX_BARS) 
    {
      throw new IllegalArgumentException("Not enough battery remains"); 
    }
  }

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

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

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

}

4 Answers

Alexander Rose
Alexander Rose
3,376 Points

Your newLaps variable represents the amount of bars after having driven the given number of laps. You want to compare this variable to 0, not the maximum amount of bars. If newLaps is less than zero, that means we didn't have enough bars to drive the given amount of laps, so throw the exception. If not, decrease mBars by the amount of laps.

Admire Dhodho
Admire Dhodho
5,411 Points

m still stuck guys

Jakob Pupke
Jakob Pupke
3,025 Points
Jakob Pupke
Jakob Pupke
3,025 Points

Alexander is right. You need to check if newLaps is greater than mBarsCount.

if ( newLaps > mBarsCount ) {
   throw new IllegalArgumentException("Not enough battery remains");
}
else {
   // is charged enough, substract newLaps from mBarsCount
   mBarsCount -= newLaps;
}
Admire Dhodho
Admire Dhodho
5,411 Points
Admire Dhodho
Admire Dhodho
5,411 Points

still failing to break it

Teferi Heye
Teferi Heye
3,448 Points
Teferi Heye
Teferi Heye
3,448 Points

`html <p>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 currentLaps= mBarsCount-laps; if (currentLaps<0){ throw new IllegalArgumentException("Not Enough Battery remains"); } }

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

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

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

}</p> `