harnessing the power of objects

Question

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);
  }

  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;
  }

}

Answer 1 · 2015-01-14T15:37:23Z

January 14, 2015 3:37pm

In the drive() method you have to try to call the drive(int laps) method and catch any error when it occurs. In the drive(int laps) method you can add a check to see if the remaining battery power (mBarsCount) is enough to drive the laps. When it runs out of battery you have to throw an exception with a message. This exception and message are then watched in the drive() method where you can print the message out to the console.

public void drive() {
    try {
      drive(1);
    } catch(IllegalArgumentException iae) {
      System.out.println(iae);
    }
  }

  public void drive(int laps) {
    // Other driving code omitted for clarity purposes
    if (mBarsCount-laps<=0) {
      throw(new IllegalArgumentException("Not enough battery remains"));
    }

    mBarsCount -= laps;
  }

Answer 2 · 2015-04-14T20:50:05Z

April 14, 2015 8:50pm

Try:

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
    if (laps > mBarsCount) {
      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;
  }

}

Welcome to the Treehouse Community

Looking to learn something new?

MUZ140151 Gilbert Chapara

MUZ140151 Gilbert Chapara

harnessing the power of objects

2 Answers

Jeroen de Vrind

Jeroen de Vrind

ISAIAH S

ISAIAH S