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

Ramis Khan
Ramis Khan
767 Points
Posted by Ramis Khan
Ramis Khan
767 Points

Exceptions getting an error

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".

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 battery remains ");
  }

  public void drive(int laps) {
    // Other driving code omitted for clarity purposes
   throw new IllegalArgumentException("Not enough battery remains ");
    mBarsCount -= laps;


  }

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

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

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

}

1 Answer

Alistair Mackay
Alistair Mackay
7,812 Points
Alistair Mackay
Alistair Mackay
7,812 Points

When you run this through compiler it says you have an unreachable code statement on line 24. Basically, when the compiler hits your throw IllegalArgumentException it ignores the rest of the code in that function. Also, your IllegalArgumentException on line 18 is not required.

For this task you want to put your illegal argument exception within an 'if' conditional that checks mBarsCount is less than laps variables.

The below code will get you started - see if you can replace the comments (sudo-code) below with the code you need to pass the test.

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) {
    if(/* conditional that checks mBarsCount is less than laps variables. */) {
    /*Your Illegal Argument exception.*/
    }
    mBarsCount -= laps;

  }

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

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

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

}