Sort3

// Fig. 20.9: Sort3.java
// Collections method sort with a custom Comparator object.
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;

public class Sort3 
{
   public static void main( String[] args )
   {
      List< Time2 > list = new ArrayList< Time2 >(); // create List

      list.add( new Time2(  6, 24, 34 ) );
      list.add( new Time2( 18, 14, 58 ) );
      list.add( new Time2(  6, 05, 34 ) );
      list.add( new Time2( 12, 14, 58 ) );
      list.add( new Time2(  6, 24, 22 ) );
      
      // output List elements
      System.out.printf( "Unsorted array elements:\n%s\n", list );

      // sort in order using a comparator
      Collections.sort( list, new TimeComparator() ); 

      // output List elements
      System.out.printf( "Sorted list elements:\n%s\n", list );
   } // end main
} // end class Sort3

// Fig. 20.8: TimeComparator.java
// Custom Comparator class that compares two Time2 objects.
import java.util.Comparator;

public class TimeComparator implements Comparator< Time2 > 
{
   public int compare( Time2 time1, Time2 time2 )
   {
      int hourCompare = time1.getHour() - time2.getHour(); // compare hour
         
      // test the hour first
      if ( hourCompare != 0 )
         return hourCompare;
         
      int minuteCompare = 
         time1.getMinute() - time2.getMinute(); // compare minute
         
      // then test the minute
      if ( minuteCompare != 0 )
         return minuteCompare;
         
      int secondCompare = 
         time1.getSecond() - time2.getSecond(); // compare second

      return secondCompare; // return result of comparing seconds
   } // end method compare
} // end class TimeComparator

// Fig. 8.5: Time2.java
// Time2 class declaration with overloaded constructors.  

public 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; ensures that Time2 objects start in a consistent state
   public Time2()
   {
      this( 0, 0, 0 ); // invoke Time2 constructor with three arguments
   } // end Time2 no-argument constructor

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

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

   // Time2 constructor: hour, minute and second supplied
   public Time2( int h, int m, int s ) 
   { 
      setTime( h, m, s ); // invoke setTime to validate time
   } // end Time2 three-argument constructor 

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

   // Set Methods
   // set a new time value using universal time; ensure that 
   // the data remains consistent by setting invalid values to zero
   public void setTime( int h, int m, int s )
   {
      setHour( h );   // set the hour
      setMinute( m ); // set the minute
      setSecond( s ); // set the second
   } // end method setTime

   // validate and set hour 
   public void setHour( int h ) 
   { 
      hour = ( ( h >= 0 && h < 24 ) ? h : 0 ); 
   } // end method setHour

   // validate and set minute 
   public void setMinute( int m ) 
   { 
      minute = ( ( m >= 0 && m < 60 ) ? m : 0 ); 
   } // end method setMinute

   // validate and set second 
   public void setSecond( int s ) 
   { 
      second = ( ( s >= 0 && s < 60 ) ? s : 0 ); 
   } // end method setSecond

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

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

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

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

   // 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" ) );
   } // end method toString
} // end class Time2