EECS1030Z Test 3

Wednesday February 25, 2015, 14:30-15:45
Lab 02
Version D

package test3;

/**
 * A class that represents time in one day using hours and minutes. The time is
 * based on a 24-hour clock: The start of each day is midnight or 0 hours and 0
 * minutes, noon is 12 hours and 0 minutes, and the end of the day is 23 hours
 * and 59 minutes.
 * 
 * <p>
 * The time represented by <code>SimpleTime</code> does not automatically change
 * with the passing of time; a client is able to manually set the time using the
 * provided mutator methods.
 * 
 * @author EECS1030_2014_15_W
 * 
 */
public class SimpleTime implements Comparable<SimpleTime> {
  
  /**
   * The hour for noon.
   */
  public static final int NOON_HOUR = 12;
  
  /**
   * The number of minutes in an hour 
   */
  public static final int MINUTES_PER_HOUR = 60;
  
  
  private int hour;
  private int minute;

  
  /**
   * Create a <code>SimpleTime</code> object that represents the same time as
   * another <code>SimpleTime</code> object.
   * 
   * @param other
   *          the <code>SimpleTime</code> object to copy
   */
  public SimpleTime(SimpleTime other) {
    this(other.getHour(), other.getMinute());
  }

  /**
   * Create a <code>SimpleTime</code> representing the time with the given hour
   * and minute.
   * 
   * @param hour
   *          the hour of the day
   * @param minute
   *          the minute of the hour
   * @throws IllegalArgumentException
   *           if <code>hour</code> is not in the range 0-23
   * @throws IllegalArgumentException
   *           if <code>minute</code> is not in the range 0-59
   */
  public SimpleTime(int hour, int minute) {
    this.setHour(hour);
    this.setMinute(minute);
  }

  /**
   * Get the hour of the day (0-23) represented by this object.
   * 
   * @return the hour
   */
  public int getHour() {
    return this.hour;
  }

  /**
   * Set the hour of the day (0-23) represented by this object.
   * 
   * @param hour
   *          the hour to set
   * @throws IllegalArgumentException
   *           if <code>hour</code> is not in the range 0-23
   */
  public void setHour(int hour) {
    if (hour < 0 || hour > 23) {
      throw new IllegalArgumentException("hour must be between 0-23");
    }
    this.hour = hour;
  }

  /**
   * Get the minute of the hour (0-59) represented by this object.
   * 
   * @return the minute
   */
  public int getMinute() {
    return minute;
  }

  /**
   * Set the minute of the hour (0-59) represented by this object.
   * 
   * @param minute
   *          the minute to set
   * @throws IllegalArgumentException
   *           if <code>minute</code> is not in the range 0-59
   */
  public void setMinute(int minute) {
    if (minute < 0 || minute > 59) {
      throw new IllegalArgumentException("minute must be between 0-59");
    }
    this.minute = minute;
  }

  /**
   * Compares this <code>SimpleTime</code> object to another
   * <code>SimpleTime</code> object.
   * 
   * <p>
   * The result is the difference in minutes between <code>this</code> time and
   * the <code>other</code> time. For example, if the time represented by
   * <code>this</code> time is 11:00 and the time represented by
   * <code>other</code> time is 13:05 then <code>this.compareTo(other)</code> returns
   * <code>-125</code>.
   * 
   * @return the difference in minutes between <code>this</code> time and the
   *         <code>other</code> time.
   */
  @Override
  public int compareTo(SimpleTime other) {
    int hour = this.getHour();
    int minutes = this.getMinute() + hour * SimpleTime.MINUTES_PER_HOUR;

    int otherHour = other.getHour();
    int otherMinutes = other.getMinute() + otherHour * SimpleTime.MINUTES_PER_HOUR;
    return minutes - otherMinutes;
  }

  
  /**
   * Returns the <code>SimpleTime</code> object equal to noon (12:00)
   * 
   * @return the <code>SimpleTime</code> object equal to noon (12:00)
   */
  public static SimpleTime noon() {
    return new SimpleTime(SimpleTime.NOON_HOUR, 0);
  }
  


  /**
   * Generate a hash code for this object.
   * 
   * @return a hash code for this object
   */
  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + this.hour;
    return result;
  }

  /**
   * Compare this <code>SimpleTime</code> to an object for equality.
   * 
   * <p>
   * The result is <code>true</code> if and only if <code>obj</code> is a
   * <code>SimpleTime</code> object, and both objects represent the same time of
   * day (i.e., identical hour, minute, and AM/PM).
   * 
   * @return <code>true</code> if both <code>SimpleTime</code> objects represent
   *         the same time of day.
   */
  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj == null) {
      return false;
    }
    if (this.getClass() != obj.getClass()) {
      return false;
    }
    SimpleTime other = (SimpleTime) obj;
    if (this.hour != other.hour) {
      return false;
    }
    if (this.minute != other.minute) {
      return false;
    }
    return true;
  }

  /**
   * Returns a string representation of the time of day. The string has the
   * format <code>XX:YY</code> where <code>XX</code> is the hour of the day and
   * <code>YY</code> is the minute of the day. Both the hour and minute fields
   * are always two characters wide.
   * 
   * @return the time of day represented by this object as a string
   */
  public String toString() {
    return String.format("%2d:%02d", this.getHour(), this.getMinute());
  }
}

Other questions

public static void main(String[] args) {
  SimpleTime t = new SimpleTime(14, 30);
  SimpleTime u = new SimpleTime(15, 45);
  SimpleTime v = u;
  // HERE
  
  // remainder of main not shown
}

/**
 * Set the minute of the hour (0-59) represented by this object.
 * 
 * @param minute
 *          the minute to set
 * @throws IllegalArgumentException
 *           if minute is not in the range 0-59
 */
public void setMinute(int minute) {
  this.minute = minute;
  
  // -now validate the value of minute:
  //
  // if minute is not in the range 0-59
  //    then throw an IllegalArugmentException here
}

SimpleTime t = new SimpleTime();
try {
  t.setMinute(-1);
}
catch (IllegalArgumentException x) {
  // DO NOTHING
}
// t.getMinute() now returns -1