//  HistoricalEvents.java (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2014-12-30  File created.
//  2017-02-24  Last modification.

//  This is a new version of the textbook program Events.java.
//  This version uses the new standard Java class LocalDate to
//  handle time-related information.

/*  This program shows
      - how a class can implement the Comparable<T> interface
      - how to create and use ArrayList-based arrays
      - how to use the static Collections.sort() method.
*/

import java.time.LocalDate ;

import java.util.ArrayList ;
import java.util.Collections ;

class  Event implements Comparable<Event>
{
   protected LocalDate date_of_event ;

   protected String event_description ;

   public Event( int  year_of_event,
                 int  month_of_event,
                 int  day_of_event,
                 String given_event_description )
   {
      date_of_event = LocalDate.of( year_of_event, month_of_event,
                                    day_of_event ) ;

      event_description  =  given_event_description ;
   }


   public String toString()
   {
      return ( date_of_event  +  "   "  +  event_description ) ;
   }

   public int compareTo( Event event_to_compare_to )
   {
      int  comparison_result  =  0 ;  //  Events of the same date.

      if ( date_of_event.isBefore( event_to_compare_to.date_of_event ) )
      {
         comparison_result  =  -1 ;   //  "this" has earlier date.
      }
      else if ( date_of_event.isAfter( event_to_compare_to.date_of_event ) )
      {
         comparison_result  =  1 ;    //  "this" has later date.
      }

      return  comparison_result ;
   }
}


class  HistoricalEvents
{
   public static void main( String[] not_in_use )
   {
      Event  birth_of_lennon   =  new  Event(
                 1940, 10, 9, "John Lennon was born.") ;
      Event  birth_of_einstein =  new  Event(
                 1879, 3, 14, "Albert Einstein was born." ) ;

      ArrayList<Event>  list_of_events  =  new  ArrayList<Event>() ;

      list_of_events.add( birth_of_lennon ) ;
      list_of_events.add( birth_of_einstein ) ;
      list_of_events.add( new
          Event( 1980, 12, 8, "John Lennon was shot in New York." ) ) ;

      System.out.print( "\nEvents of list_of_events: \n" ) ;

      int event_index  =  0 ;

      while ( event_index  <  list_of_events.size() )
      {
         System.out.print( "\n   "  +  list_of_events.get( event_index ) ) ;
         event_index  ++  ;
      }


      ArrayList<Event>  another_event_list  =  new  ArrayList<Event>() ;

      another_event_list.add( 0,
         new Event( 1926, 6, 1, "Marilyn Monroe was born." ) ) ;
      another_event_list.add( 0,
         new Event( 1962, 8, 5, "Marilyn Monroe died." ) ) ;
      another_event_list.add(
         new Event( 1769, 8, 15, "Napoleon Bonaparte was born." ) ) ;
      another_event_list.add(
         new Event( 1881, 10, 25, "Pablo Picasso was born." ) ) ;


      System.out.print( "\n\nEvents of another_event_list: \n" ) ;

      for ( event_index  =  0 ;
            event_index  <  another_event_list.size() ;
            event_index  ++ )
      {
         System.out.print( "\n   "  +  another_event_list.get( event_index ) );
      }

      Collections.sort( list_of_events ) ;
      Collections.sort( another_event_list ) ;

      list_of_events.addAll( 0, another_event_list ) ;

      // Next, we use a 'foreach' loop to print all objects in the
      // ArrayList-based list.

      System.out.print( "\n\nEvents of list_of_events: \n" ) ;

      for ( Event event_to_print : list_of_events )
      {
         System.out.print( "\n   "  +  event_to_print ) ;
      }

      System.out.print( "\n\n" ) ;
   }
}


/* NOTES:

   In modern Java, another possibility to sort the above
   arrays is to use the statements

      list_of_events.sort( null ) ;
      another_event_list.sort( null ) ;

   The null as a parameter means that the natural ordering of the
   objects should be used.


   Useful pages related to this program:

      https://docs.oracle.com/javase/8/docs/api/java/util/ArrayList.html

      http://docs.oracle.com/javase/8/docs/api/java/lang/Comparable.html

*/