//  IterableArrayDemo.java (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2017-02-24  File created.
//  2017-02-24  Last modification.


/*  This program ís a modified version of the example program named
    HistoricalEvents.java

    In this program the used arrays are of type IterableArray, which
    is defined in this file.

    Objects of IterableArray contain a built-in iteration mechanism.

    I wrote this after I started to wonder why we have such things
    as separate iterators, and why they are not built-in in such 
    classes as the standard ArrayList class.

*/

import java.time.LocalDate ;

import java.util.* ;


class  IterableArray<E> extends ArrayList<E>
{
   Iterator<E> iterator_for_this_array = null ;

   // The following method must be called always before a new iteration loop.

   public void setIterable()
   {
      iterator_for_this_array = iterator() ;
   }

   public boolean hasNext()
   {
      return iterator_for_this_array.hasNext() ;
   }

   public E next()
   {
      return iterator_for_this_array.next() ;
   }
}


// Objects of class Event are used to test the IterableArray class.

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 IterableArrayDemo
{
   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." ) ;

      IterableArray<Event>  list_of_events  =  new  IterableArray<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" ) ;

      list_of_events.setIterable() ;

      while ( list_of_events.hasNext() )
      {
         System.out.print( "\n   "  +  list_of_events.next() ) ;
      }


      IterableArray<Event>  another_event_list  =  new  IterableArray<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" ) ;

      another_event_list.setIterable() ;

      while( another_event_list.hasNext() )
      {
         System.out.print( "\n   "  +  another_event_list.next() );
      }

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

      list_of_events.addAll( 0, another_event_list ) ;

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

      list_of_events.setIterable() ;

      while ( list_of_events.hasNext() )
      {
         System.out.print( "\n   "  +  list_of_events.next() ) ;
      }


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


/*    // The following code was tested as well.


      IterableArray<String> month_names = new IterableArray<String>() ;

      Collections.addAll( month_names, "January", "February", "March", "April" ) ;


      System.out.print( "\n\nMonth names: \n" ) ;

      month_names.setIterable() ;

      while ( month_names.hasNext() )
      {
         System.out.print( "\n   "  +  month_names.next() ) ;
      }

*/