迭代器模式解决学校院系结构展示问题

• 案例说明

要在一个页面中展示出学校的院系组成，一个学校有多个学院，一个学院有多个系

• 设计类图
  

• 代码实现

package com.atguigu.iterator;
public class Department {

	private String name;
	
	private String desc;
	
	public Department(String name, String desc) {
		super();
		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.atguigu.iterator;
import java.util.Iterator;
public class ComputerCollegeIterator implements Iterator {

	//这里我们需要Department 是以怎样的方式存放=>数组
	Department[] departments;
	
	int position = 0; //遍历的位置
	
	public ComputerCollegeIterator(Department[] departments) {
		this.departments = departments;
	}

	//判断是否还有下一个元素
	@Override
	public boolean hasNext() {
		// TODO Auto-generated method stub
		if(position >= departments.length || departments[position] == null) {
			return false;
		}else {
			return true;
		}
	}

	@Override
	public Object next() {
		// TODO Auto-generated method stub
		Department department = departments[position];
		position += 1;
		return department;
	}
	
	//删除的方法，默认空实现
	public void remove() {
	}

}

package com.atguigu.iterator;
import java.util.Iterator;
import java.util.List;
public class InfoColleageIterator implements Iterator {
	
	List<Department> departmentList; // 信息工程学院是以List方式存放系
	
	int index = -1;//索引

	public InfoColleageIterator(List<Department> departmentList) {
		this.departmentList = departmentList;
	}

	//判断list中还有没有下一个元素
	@Override
	public boolean hasNext() {
		// TODO Auto-generated method stub
		if(index >= departmentList.size() - 1) {
			return false;
		} else {
			index += 1;
			return true;
		}
	}

	@Override
	public Object next() {
		// TODO Auto-generated method stub
		return departmentList.get(index);
	}
	
	//空实现remove
	public void remove() {
	}

}

package com.atguigu.iterator;
import java.util.Iterator;
public interface College {
	
	public String getName();
	
	//增加系的方法
	public void addDepartment(String name, String desc);
	
	//返回一个迭代器,遍历
	public Iterator  createIterator();
}

package com.atguigu.iterator;
import java.util.Iterator;
public class ComputerCollege implements College {

	Department[] departments;
	
	int numOfDepartment = 0 ;// 保存当前数组的对象个数
	
	public ComputerCollege() {
		departments = new Department[5];
		addDepartment("Java专业", " Java专业 ");
		addDepartment("PHP专业", " PHP专业 ");
		addDepartment("大数据专业", " 大数据专业 ");
	}
	
	@Override
	public String getName() {
		// TODO Auto-generated method stub
		return "计算机学院";
	}

	@Override
	public void addDepartment(String name, String desc) {
		// TODO Auto-generated method stub
		Department department = new Department(name, desc);
		departments[numOfDepartment] = department;
		numOfDepartment += 1;
	}

	@Override
	public Iterator createIterator() {
		// TODO Auto-generated method stub
		return new ComputerCollegeIterator(departments);
	}

}

package com.atguigu.iterator;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class InfoCollege implements College {

	List<Department> departmentList;
	
	public InfoCollege() {
		departmentList = new ArrayList<Department>();
		addDepartment("信息安全专业", " 信息安全专业 ");
		addDepartment("网络安全专业", " 网络安全专业 ");
		addDepartment("服务器安全专业", " 服务器安全专业 ");
	}
	
	@Override
	public String getName() {
		// TODO Auto-generated method stub
		return "信息工程学院";
	}

	@Override
	public void addDepartment(String name, String desc) {
		// TODO Auto-generated method stub
		Department department = new Department(name, desc);
		departmentList.add(department);
	}

	@Override
	public Iterator createIterator() {
		// TODO Auto-generated method stub
		return new InfoColleageIterator(departmentList);
	}

}

package com.atguigu.iterator;
import java.util.Iterator;
import java.util.List;
public class OutPutImpl {
	
	//学院集合
	List<College> collegeList;

	public OutPutImpl(List<College> collegeList) {
		this.collegeList = collegeList;
	}
	//遍历所有学院,然后调用printDepartment 输出各个学院的系
	public void printCollege() {
		
		//从collegeList 取出所有学院, Java 中的 List 已经实现Iterator
		Iterator<College> iterator = collegeList.iterator();
		
		while(iterator.hasNext()) {
			//取出一个学院
			College college = iterator.next();
			System.out.println("=== "+college.getName() +"=====" );
			printDepartment(college.createIterator()); //得到对应迭代器
		}
	}
	
	//输出 学院输出 系
	public void printDepartment(Iterator iterator) {
		while(iterator.hasNext()) {
			Department d = (Department)iterator.next();
			System.out.println(d.getName());
		}
	}
	
}

package com.atguigu.iterator;
import java.util.ArrayList;
import java.util.List;
public class Client {

	public static void main(String[] args) {
		//创建学院
		List<College> collegeList = new ArrayList<College>();
		
		ComputerCollege computerCollege = new ComputerCollege();
		InfoCollege infoCollege = new InfoCollege();
		
		collegeList.add(computerCollege);
		//collegeList.add(infoCollege);
		
		OutPutImpl outPutImpl = new OutPutImpl(collegeList);
		outPutImpl.printCollege();
	}

}