迭代器模式【Iterator Pattern】

Iterator，迭代器模式：提供一个方法顺序访问一个聚合对象的各个元素，而又不需要暴露该对象的内部表示。

package com.cbf4life;

 public interface IProject {
 //从老板这里看到的就是项目信息
 public String getProjectInfo();
 }

 package com.cbf4life;
 public class Project implements IProject {
 //项目名称
 private String name = "";
 //项目成员数量
 private int num = 0;
 //项目费用
 private int cost = 0;

 public Project(String name,int num,int cost){
 this.name = name;
 this.num = num;
 this.cost=cost;
 }

 public String getProjectInfo() {
 String info = "";
 info = info+ "项目名称是：" + this.name;
 info = info + "\t项目人数: "+ this.num;
 info = info+ "\t 项目费用："+ this.cost;
 return info;
 }
 }


 package com.cbf4life;
 import java.util.ArrayList;
 /**
 * 老板来看项目信息了
 */
 public class Boss {
 public static void main(String[] args) {

 ArrayList<IProject> projectList = new ArrayList<IProject>();

 projectList.add(new Project("星球大战项目",10,100000));

 projectList.add(new Project("扭转时空项目",100,10000000));

 projectList.add(new Project("超人改造项目",10000,1000000000));

 for(int i=4;i<104;i++){
 projectList.add(new Project("第"+i+"个项目",i*5,i*1000000));
 }for(IProject project:projectList){
 System.out.println(project.getProjectInfo());
 }
 }
 }
 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 package com.cbf4life.pattern;
 public interface IProject {
 //增加项目
 public void add(String name,int num,int cost);
 //从老板这里看到的就是项目信息
 public String getProjectInfo();
 //获得一个可以被遍历的对象
 public IProjectIterator iterator();
 } package com.cbf4life.pattern;
 import java.util.ArrayList;
 @SuppressWarnings("all")
 public class Project implements IProject {
 private ArrayList<IProject> projectList = new ArrayList<IProject>();
 private String name = "";
 private 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;
 }

 public void add(String name,int num,int cost){
 this.projectList.add(new Project(name,num,cost));
 }
 public String getProjectInfo() {
 String info = "";
 info = info+ "项目名称是：" + this.name;
 info = info + "\t项目人数: "+ this.num;
 info = info+ "\t 项目费用："+ this.cost;
 return info;
 }

 public IProjectIterator iterator(){
 return new ProjectIterator(this.projectList);
 }
 }

 package com.cbf4life.pattern;
 import java.util.Iterator;
 @SuppressWarnings("all")
 public interface IProjectIterator extends Iterator {
 }

 package com.cbf4life.pattern;
 import java.util.ArrayList;

 public class ProjectIterator implements IProjectIterator {

 private ArrayList<IProject> projectList = new ArrayList<IProject>();
 private int currentItem = 0;
 //构造函数传入projectList
 public ProjectIterator(ArrayList<IProject> projectList){
 this.projectList = projectList;
 }
 //判断是否还有元素，必须实现
 public boolean hasNext() {
 //定义一个返回值
 boolean b = true;
 if(this.currentItem>=projectList.size() ||
 this.projectList.get(this.currentItem) == null){
 b =false;
 }
 return b;
 }
 //取得下一个值
 public IProject next() {
 return (IProject)this.projectList.get(this.currentItem++);
 }
 //删除一个对象
 public void remove() {
 //暂时没有使用到
 }
 }
 //都写完毕了，然后看看我们的Boss 类有多少改动：
 package com.cbf4life.pattern;
 public class Boss {
 public static void main(String[] args) {

 IProject project = new Project();

 project.add("星球大战项目ddddd",10,100000);

 project.add("扭转时空项目",100,10000000);

 project.add("超人改造项目",10000,1000000000);
 //这边100个项目
 for(int i=4;i<104;i++){
 project.add("第"+i+"个项目",i*5,i*1000000);
 }


 IProjectIterator projectIterator = project.iterator();
 while(projectIterator.hasNext()){
 IProject p = (IProject)projectIterator.next();
 System.out.println(p.getProjectInfo());
 }
 }
 }