Design Pattern iterator mode

iterator pattern definition: It provides a way to access individual elements in a container object without exposing the internal details of the object.

(Iterators are serviced for containers.) All types that can hold an object can be called containers. For example: Collection collection type, map type. Since the collection now provides iterators, this pattern is rarely applied at this time)

Iterators have the following roles:

1, iterator abstract iterator. There are three basic methods: Hasnext (), Next (), remove ().

2, Concreteiterator specific iterators.

3, aggregate abstract container.

4, concreteaggregate specific containers.

The class diagram is as follows:

The implementation code is as follows:

Abstract iterator:

Package Com.designpatterns.iterator;import java.util.iterator;/** * @author WSYW126 * @version May 5, 2016 6:42:28 * * Public interface Iprojectiterator extends iterator<object> {}

Iterator implementation class:

Package Com.designpatterns.iterator;import java.util.arraylist;/** * @author WSYW126 * @version May 5, 2016 6:43:37 * * public class Projectiterator implements Iprojectiterator {private arraylist<iproject> rs = new arraylist<> () ;p rivate int currentitem = 0;public Projectiterator (arraylist<iproject> rs) {this.rs = rs;} @Overridepublic Boolean Hasnext () {Boolean b = false;if (This.currentitem < This.rs.size ()) {b = true;} return b;} @Overridepublic IProject Next () {return this.rs.get (currentitem++);} @Overridepublic void Remove () {}}

Abstract Container:

Package com.designpatterns.iterator;/** * @author WSYW126 * @version May 5, 2016 PM 6:45:09 */public interface IProject {Publ IC void Add (string name, int num, int cost);p ublic String getprojectinfo ();p ublic Iprojectiterator iterator ();}

Container Implementation class:

Package Com.designpatterns.iterator;import java.util.arraylist;/** * @author WSYW126 * @version May 5, 2016 6:49:21 * * public class Project implements IProject {private arraylist<iproject> rs = new arraylist<> ();p rivate String na me = "";p rivate int num = 0;private int cost = 0;public Project () {}private project (String name, int num, int. cost) {this. Name = Name;this.num = Num;this.cost = Cost;} @Overridepublic void Add (String name, int num, int cost) {This.rs.add (new Project (name, num, cost));} @Overridepublic string Getprojectinfo () {String inf = ""; inf = inf + "Project name is:" + This.name;inf = inf + "\ T Project number:" + this.nu M;inf = inf + "\ T project cost:" + This.cost;return inf;} @Overridepublic Iprojectiterator iterator () {return new projectiterator (this.rs);}

Test class:

Package com.designpatterns.iterator;/** * @author WSYW126 * @version May 6, 2016 PM 6:06:13 */public class Boss {public static void Main (string[] args) {IProject project = new Project ();p Roject.add ("StarCraft", Max.);p Roject.add ("Superhero", 100, 100000) ; for (int i = 0; i < i++) {Project.add ("+ i +" items ", I * 5, I * 10000);} Iprojectiterator projectiterator = Project.iterator (); while (Projectiterator.hasnext ()) {IProject p = (IProject) Projectiterator.next (); System.out.println (P.getprojectinfo ());}}}

This is the iterator pattern.

References :
The Zen of design pattern

Remark :
Reprint please indicate the source
http://blog.csdn.net/wsyw126/article/details/51333750
by WSYW126

Design Pattern iterator mode