Class declaration with overloaded constructors

Description

Demo Code

public class Main 
{
   public static void main(String[] args)
   {/*from w ww .j  ava 2s. c  o m*/
      Time2 t1 = new Time2();       // 00:00:00
      Time2 t2 = new Time2(2);      // 02:00:00
      Time2 t3 = new Time2(21, 31); // 21:31:00
      Time2 t4 = new Time2(12, 25, 42); // 12:25:42
      Time2 t5 = new Time2(t4);         // 12:25:42

      System.out.println("Constructed with:");
      displayTime("t1: all default arguments", t1);
      displayTime("t2: hour specified; default minute and second", t2);
      displayTime("t3: hour and minute specified; default second", t3);
      displayTime("t4: hour, minute and second specified", t4);
      displayTime("t5: Time2 object t4 specified", t5);

      // attempt to initialize t6 with invalid values
      try
      {
         Time2 t6 = new Time2(27, 74, 99); // invalid values
      } 
      catch (IllegalArgumentException e)
      {
         System.out.printf("%nException while initializing t6: %s%n",
            e.getMessage());
      } 
   } 

   // displays a Time2 object in 24-hour and 12-hour formats
   private static void displayTime(String header, Time2 t)
   {
      System.out.printf("%s%n   %s%n   %s%n",
         header, t.toUniversalString(), t.toString());
   } 
}


class Time2
{
   private int hour; // 0 - 23
   private int minute; // 0 - 59
   private int second; // 0 - 59

   // Time2 no-argument constructor: 
   // initializes each instance variable to zero
   public Time2()
   {
      this(0, 0, 0); // invoke constructor with three arguments
   } 

   // Time2 constructor: hour supplied, minute and second defaulted to 0
   public Time2(int hour) 
   { 
      this(hour, 0, 0); // invoke constructor with three arguments
   } 

   // Time2 constructor: hour and minute supplied, second defaulted to 0
   public Time2(int hour, int minute) 
   { 
      this(hour, minute, 0); // invoke constructor with three arguments
   } 

   // Time2 constructor: hour, minute and second supplied
   public Time2(int hour, int minute, int second) 
   { 
      if (hour < 0 || hour >= 24)
         throw new IllegalArgumentException("hour must be 0-23");

      if (minute < 0 || minute >= 60)
         throw new IllegalArgumentException("minute must be 0-59");

      if (second < 0 || second >= 60)
         throw new IllegalArgumentException("second must be 0-59");

      this.hour = hour;
      this.minute = minute; 
      this.second = second; 
   } 

   // Time2 constructor: another Time2 object supplied
   public Time2(Time2 time)
   {
      // invoke constructor with three arguments
      this(time.getHour(), time.getMinute(), time.getSecond());
   } 

   public void setTime(int hour, int minute, int second)
   {
      if (hour < 0 || hour >= 24)
         throw new IllegalArgumentException("hour must be 0-23");

      if (minute < 0 || minute >= 60)
         throw new IllegalArgumentException("minute must be 0-59");

      if (second < 0 || second >= 60)
         throw new IllegalArgumentException("second must be 0-59");

      this.hour = hour;
      this.minute = minute; 
      this.second = second; 
   } 

   // validate and set hour 
   public void setHour(int hour) 
   { 
      if (hour < 0 || hour >= 24)
         throw new IllegalArgumentException("hour must be 0-23");

      this.hour = hour;
   } 

   // validate and set minute 
   public void setMinute(int minute) 
   { 
      if (minute < 0 || minute >= 60)
         throw new IllegalArgumentException("minute must be 0-59");

      this.minute = minute; 
   } 

   // validate and set second 
   public void setSecond(int second) 
   { 
      if (second < 0 || second >= 60)
         throw new IllegalArgumentException("second must be 0-59");

       this.second = second; 
   } 

   // Get Methods
   // get hour value
   public int getHour() 
   { 
      return hour; 
   } 

   // get minute value
   public int getMinute() 
   { 
      return minute; 
   } 

   // get second value
   public int getSecond() 
   { 
      return second; 
   } 

   // convert to String in universal-time format (HH:MM:SS)
   public String toUniversalString()
   {
      return String.format(
         "%02d:%02d:%02d", getHour(), getMinute(), getSecond());
   } 

   // convert to String in standard-time format (H:MM:SS AM or PM)
   public String toString()
   {
      return String.format("%d:%02d:%02d %s", 
         ((getHour() == 0 || getHour() == 12) ? 12 : getHour() % 12),
         getMinute(), getSecond(), (getHour() < 12 ? "AM" : "PM"));
   } 
}
Class declaration with overloaded constructors - Java Object Oriented Design

Description

Demo Code

Result

Related Tutorials
