public ArraySet(Collection<? extends E> collection){
  items=new ArrayList<E>(collection.size());
  for (  E item : collection)   if (!items.contains(item))   items.add(item);
}

public ArraySet ( Collection < ? extends E > collection ) { items = new ArrayList < E > ( collection . size ( ) ) ; for ( E item : collection ) if ( ! items . contains ( item ) ) items . add ( item ) ; }
create a set containing the items of the collection . any duplicate items are discarded .
