需求案例
使用传统的设计方案
传统解决方案存在的问题
迭代器模式的基本介绍
迭代器模式的原理类图
迭代器模式应用实例
代码实现
package com.sky.iterator;
import java.util.Iterator;
// 学院接口
public interface College {
// 获取学院的名字
String getCollegeName();
// 添加院系
void addDepartment(Department department);
// 获取迭代器
Iterator getIterator();
}
package com.sky.iterator;
import java.util.Iterator;
// 学院的实现类
public class ComputerCollege implements College {
private Department[] departments;
private int num = 0; // 记录数组的对象数
public ComputerCollege(){
departments = new Department[4];
departments[0] = new Department("计算机科学与技术","计算机科学与技术描述");
departments[1] = new Department("软件工程","软件工程描述");
departments[2] = new Department("网络工程","网络工程描述");
departments[3] = new Department("大数据","大数据描述");
}
@Override
public String getCollegeName() {
return "计算机学院";
}
@Override
public void addDepartment(Department department) {
departments[num++] = department;
}
@Override
public Iterator getIterator() {
return new ComputerIterator(departments);
}
}
package com.sky.iterator;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class InfoManagerCollege implements College {
private List<Department> list;
public InfoManagerCollege(){
list = new ArrayList<>();
list.add(new Department("信息分析","信息分析描述"));
list.add(new Department("信息统计","信息统计描述"));
list.add(new Department("信息抽取","信息抽取描述"));
}
@Override
public String getCollegeName() {
return "信息工程学院";
}
@Override
public void addDepartment(Department department) {
list.add(department);
}
@Override
public Iterator getIterator() {
return new InfoManagerIterator(list);
}
}
package com.sky.iterator;
public class Department {
private String name; // 院系名称
private String desc; // 院系描述
public Department(String name, String desc) {
this.name = name;
this.desc = desc;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
}
package com.sky.iterator;
import java.util.Iterator;
/**
* 计算机学院 的 迭代器
*/
public class ComputerIterator implements Iterator {
private Department[] departments; // 假设计算机学院中的系是以数组的形式保存的
private int index; // 下标 遍历的时候用到
public ComputerIterator(Department[] departments){
this.departments = departments;
}
// 判断遍历的时候，是否还存在元素
@Override
public boolean hasNext() {
if(index >= departments.length || departments[index] == null){
return false;
}
return true;
}
// 获取下一个元素
@Override
public Object next() {
return departments[index++];
}
// 移除元素
@Override
public void remove() {
// 空实现
}
}
package com.sky.iterator;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* 信息管理学院
*/
public class InfoManagerIterator implements Iterator {
private List<Department> departmentList = new ArrayList<>(); // 假设信息管理学院中的系是以List集合的方式存储的
private int position; // 下标 遍历的时候用到
public InfoManagerIterator(List<Department> departmentList){
this.departmentList = departmentList;
}
// 判断遍历的时候，是否还存在元素
@Override
public boolean hasNext() {
if(position > departmentList.size()-1 || departmentList.get(position) == null){
return false;
}
return true;
}
// 获取下一个元素
@Override
public Object next() {
return departmentList.get(position++);
}
// 移除元素
@Override
public void remove() {
// 空实现
}
}
package com.sky.iterator;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
// 打印学院院系
public class OutputCollegeImpl {
private List<College> collegeList;
public OutputCollegeImpl() {
collegeList = new ArrayList<>();
collegeList.add(new ComputerCollege());
collegeList.add(new InfoManagerCollege());
}
// 打印学院以及下面的院系
public void getCollegeAllDepartment() {
Iterator<College> iterator = collegeList.iterator();
while (iterator.hasNext()) {
// 获取到学院
College college = iterator.next();
System.out.println("==========" + college.getCollegeName() + "=========");
// 获取学院的迭代器
// 计算机学院用的数组存储，信息管理学院用的列表存储，通过迭代器可统一使用
Iterator collegeIterator = college.getIterator();
while (collegeIterator.hasNext()){
// 获取到院系
Department department = (Department) collegeIterator.next();
System.out.println(department.getName() + ":" + department.getDesc());
}
}
}
}
package com.sky.iterator;
// 客户端
public class Client {
public static void main(String[] args) {
OutputCollegeImpl outputCollege = new OutputCollegeImpl();
outputCollege.getCollegeAllDepartment();
}
}
==========计算机学院=========
计算机科学与技术:计算机科学与技术描述
软件工程:软件工程描述
网络工程:网络工程描述
大数据:大数据描述
==========信息工程学院=========
信息分析:信息分析描述
信息统计:信息统计描述
信息抽取:信息抽取描述
迭代器模式的注意事项和细节
标签：Iterator,迭代,departments,模式,Department,new,iterator,public From： https://www.cnblogs.com/dongyaotou/p/16968928.html