Design Pattern-iterators

Definition: Provides a way to sequentially access individual elements in an aggregated object without exposing their internal representations.

UML Class Diagrams:

1 InterfaceIterator {2      PublicObject Next ();3      Public BooleanHasnext ();4 }5 classConcreteiteratorImplementsiterator{6     PrivateList List =NewArrayList ();7     Private intCursor =0;8      Publicconcreteiterator (List list) {9          This. List =list;Ten     } One      Public BooleanHasnext () { A         if(cursor==list.size ()) { -             return false; -         } the         return true; -     } -      PublicObject Next () { -Object obj =NULL; +         if( This. Hasnext ()) { -obj = This. List.get (cursor++); +         } A         returnobj; at     } - } - InterfaceAggregate { -      Public voidAdd (Object obj); -      Public voidRemove (Object obj); -      PublicIterator Iterator (); in } - classConcreteaggregateImplementsAggregate { to     PrivateList List =NewArrayList (); +      Public voidAdd (Object obj) { - list.add (obj); the     } *   $      PublicIterator Iterator () {Panax Notoginseng         return Newconcreteiterator (list); -     } the   +      Public voidRemove (Object obj) { A list.remove (obj); the     } + } -  Public classClient { $      Public Static voidMain (string[] args) { $Aggregate AG =Newconcreteaggregate (); -Ag.add ("Xiao Ming"); -Ag.add ("Little Red"); theAg.add ("Xiao Gang")); -Iterator it =ag.iterator ();Wuyi          while(It.hasnext ()) { theString str =(String) It.next (); - System.out.println (str); Wu         } -     } About}

Design Pattern-iterators