Display a class named Time. (help troubleshooting code)

Question

I need to design a class named Time. The class needs to contain:

■ Data fields hour, minute, and second that represent a time.

■ A no-arg constructor that creates a Time object for the current time. (The values of the data fields will represent the current time.)

■ A constructor that constructs a Time object with a specified elapsed time since midnight, Jan 1, 1970, in milliseconds. (The values of the data fields will represent this time.)

■ A constructor that constructs a Time object with the specified hour, minute, and second.

■ Three get methods for the data fields hour, minute, and second, respectively.

■ A method named setTime(long elapseTime) that sets a new time for the object using the elapsed time.

For this task, I have created the following code:

public class Time{
   private int hour;
   private int minute;
   private int second;

   public Time(){
     this(System.currentTimeMillis());
   }

   public Time(long elapseTime){
     long totalSeconds = elapseTime / 1000L;
     this.second = (int)(totalSeconds % 60L);
     long totalMinutes = totalSeconds / 60L;
     this.minute = (int)(totalMinutes % 60L);
     int totalHours = (int)(totalMinutes / 60L);
     this.hour = (totalHours % 24);
   }

   public String toString() {
     return this.hour + ":" + this.minute + ":" + this.second + " GMT";
   }

   public int getHour() {
     return this.hour;
   }

   public int getMinute() {
     return this.minute;
   }

   public int getSecond() {
     return this.second;
 }
}

It compiles fine, but when I go to run it a dialog box pops up that says "No main methods, applets, or MIDlets found in file". Obviously my main method isn't right, but I can't seem to fix it, cause everything I've tried just creates more errors. If anyone could suggest a change to make my code work, I'd greatly appreciate it.

Edit: Yes, I orginally had it thusly:

 public class Time{
  public static void main(String args[]){...

but that had about a million errors. It seems I have the meat of it, but not the basic beginnings right.

Answer 1

You either need a main method in the Time class, or a separate class (ie "TimeTester") like this:

public class TimeTester {

  public static void main(String[] args) {

    // Test the default constructor
    Time time = new Time();

    System.out.println("time = " + time);
    System.out.println("time.toHour() " + time.toHour());
    // etc..

    // Test with a supplied value
    Time time2 = new Time(12033312L);
    System.out.println("time2 = " + time2); 
    // etc..
   }
}