06-04-设计模式 迭代器模式

package com.flower.iterator;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;

public class TestMain {
    public static void main(String[] args) {
        List<College> colleges = Arrays.asList(new ComputerCollege(), new InfoCollege());
        OutputImpl output = new OutputImpl(colleges);
        output.printCollege();
    }
}
class Dept{
    public String name;
    public String desc;

    @Override
    public String toString() {
        return "Dept{" +
                "name='" + name + '\'' +
                ", desc='" + desc + '\'' +
                '}';
    }
}
class ComputerCollegeIterator implements Iterator<Dept>{

    public Dept[] depts;

    public int position = 0;

    public ComputerCollegeIterator(Dept[] depts) {
        this.depts = depts;
    }

    @Override
    public boolean hasNext() {
        return position < depts.length && depts[position] != null;
    }

    @Override
    public Dept next() {
        return depts[position++];
    }

    @Override
    public void remove() {
        depts[position] = null;
    }
}
class InfoCollegeIterator implements Iterator<Dept>{

    public List<Dept> depts;

    public int position = 0;

    public InfoCollegeIterator(List<Dept> depts) {
        this.depts = depts;
    }

    @Override
    public boolean hasNext() {
        return position < depts.size() && depts.get(position) != null;
    }

    @Override
    public Dept next() {
        return depts.get(position++);
    }

    @Override
    public void remove() {
        depts.remove(position);
    }
}
interface College{
    String getName();
    void addDept(String name,String desc);
    Iterator<Dept> createIterator();
}
class ComputerCollege implements College{

    public Dept[] depts;

    public int index = 0;

    public ComputerCollege() {
        depts = new Dept[3];
        addDept("计算机1","计算机1");
        addDept("计算机2","计算机2");
        addDept("计算机3","计算机3");
    }

    @Override
    public String getName() {
        return "计算机学院";
    }

    @Override
    public void addDept(String name, String desc) {
        Dept dept = new Dept();
        dept.name = name;
        dept.desc = desc;
        depts[index++] = dept;
    }

    @Override
    public Iterator<Dept> createIterator() {
        return new ComputerCollegeIterator(depts);
    }
}
class InfoCollege implements College{

    public List<Dept> depts;

    public int index = 0;

    public InfoCollege() {
        depts = new ArrayList<>(3);
        addDept("信息1","信息1");
        addDept("信息2","信息2");
        addDept("信息3","信息3");
    }

    @Override
    public String getName() {
        return "信息工程学院";
    }

    @Override
    public void addDept(String name, String desc) {
        Dept dept = new Dept();
        dept.name = name;
        dept.desc = desc;
        depts.add(dept);
    }

    @Override
    public Iterator<Dept> createIterator() {
        return new InfoCollegeIterator(depts);
    }
}
class OutputImpl{
    List<College> colleges;

    public OutputImpl(List<College> colleges) {
        this.colleges = colleges;
    }

    public void printCollege(){
        colleges.forEach(college -> {
            String name = college.getName();
            System.out.println(name);
            printDept(college.createIterator());
        });
    }

    public void printDept(Iterator<Dept> iterator){
        while (iterator.hasNext()){
            Dept next = iterator.next();
            System.out.println(next);
        }
    }
}