Re: ArrayList.toString versus iterating through the ArrayList

thufir wrote:


The principle, elucidated in pretty much those words in /Effective Java/ by
Joshua Bloch, is a guideline rather than a rule. "Prefer composition" means
that in most designs it works better to include an element of type List than
to extend a List type. Sometimes the "is-a" relationship is so strong and
evident that you absolutely must inherit, but most of the time it makes at
least as much sense to use "has-a", and that makes maintenance easier.


Since Guests does nothing to add to ArrayList, it probably doesn't need a
whole new type.

  public class Lab2
  {
   private final List <Guest> guests = new ArrayList <Guest> ();

   public void print()
   {
    for ( Guest g : guests )
    {
      System.out.println( g );
    }
   }
   public boolean add( Guest g )
   {
    if ( g == null )
    { throw new NullPointerException( "null Guest" ); }
    return guests.add( g );
   }
   public static void main( String args [] )
   {
     Lab2 lab = new Lab2();
     for ( int ix = 0; ix < 9; ++ix )
     {
       lab.add( new Guest() );
     }
     lab.print();
   }
  }

--
Lew