Big talk Design Pattern _ iterator Pattern

Take bus ticket conductor as an example.

I. Self-implemented iterator

Package COM. WZS. design; import Java. util. arraylist; import Java. util. list;/*** big talk design mode -- page202 iterator mode ** @ author administrator **/public class iteratorpattern {public static void main (string [] ARGs) {concreteaggregate A = new concreteaggregate ();. set ("laruence");. set ("Pickles");. set ("Luggage");. set ("foreigner");. set ("Bus internal staff");. set ("thief"); iterator = new concreteiterator (a); While (! Iterator. iddone () {system. out. println (iterator. currentitem () + "\ t buy a ticket. "); iterator. next () ;}}/ ** iterator abstract class */abstract class iterator {// The first public abstract object first (); // next public abstract object next (); // public Abstract Boolean iddone () at the end; // The current object public abstract object currentitem ();} /** specific iterator */class concreteiterator extends iterator {private concreteaggregate aggregate; private int Current = 0; Public concreteiterator (concreteaggregate aggregate) {This. aggregate = aggregate;} @ overridepublic object first () {return aggregate. get (0) ;}@ overridepublic object next () {object ret = NULL; current ++; If (current <aggregate. count () {ret = aggregate. get (current);} return ret;} @ overridepublic object currentitem () {return aggregate. get (current) ;}@ overridepublic Boolean iddone () {return cur Rent> = aggregate. Count ()? True: false;}/** aggregate aggregation abstract class */abstract class aggregate {public abstract iterator createiterator ();} /** concreteaggregate specific aggregation class */class concreteaggregate extends aggregate {private list <Object> items = new arraylist <Object> (); @ overridepublic iterator createiterator () {return New concreteiterator (this);} public int count () {return items. size ();} public object get (INT index) {return items. get (INDEX);} public void set (object Value) {items. add (value );}}

Ii. iterator in Java

Package COM. WZS. design; import Java. util. arraylist; import Java. util. iterator; import Java. util. list; import Java. util. random;/** Java iterator */public class javaiterator {public static void main (string [] ARGs) {list <integer> List = new arraylist <integer> (); random random = new random (); For (INT I = 0; I <10; I ++) {list. add (random. nextint (20);} system. out. println ("array element:" + list); system. out. println ("Iteration Result:"); iterator <integer> iterator = List. iterator (); While (iterator. hasnext () {system. out. print (iterator. next () + "");}}}