设计模式_迭代器模式

迭代器模式

介绍

设计模式	定义	案例
迭代器模式	行为型：关注对象与行为的分离 提供了一种统一的方式来访问多个不同的集合	两个集合：使用了不同的数据存储方式 学生 和 警察 查询显示出集合的内容 ，使用相同的代码

问题堆积在哪里	解决办法
不同的存储方式 统一集合查询代码	1 统一出一个存储方式 2 设计一个查询基类来统一查询代码 3 每个集合提供   1 统一存储方式，   2 一个查询实现（接口迭代器的实现）

类图

代码

interface BaseIterator

/// 

/// 迭代器基类
/// 
public interface BaseIterator
{
    // 当前
    T Current();

    // 下一个
    bool MoveNext();

    // 重新开始
    void Reset();
}

IteratorPolice 

using System.Collections.Generic;

public class IteratorPolice : BaseIterator
{
    // 列表
    List listPeople = null;
    // 下标
    int currentIndex = -1;  

    IteratorPolice() { }
    public IteratorPolice(List list)
    {
        listPeople = list;
    }

    public People Current()
    {
        if (null == listPeople)
            return null;

        if (listPeople.Count < currentIndex)
            return null;

        return listPeople[currentIndex];
    }

    public bool MoveNext()
    {
        if (null == listPeople)
            return false;

        if (listPeople.Count > ++currentIndex)
            return true;

        return false;
    }

    public void Reset()
    {
        currentIndex = -1;
    }
}

IteratorStudent 

using System.Collections.Generic;

public class IteratorStudent : BaseIterator
{
    // 列表
    List listPeople = null;
    // 下标
    int currentIndex = -1;

    IteratorStudent() { }
    public IteratorStudent(List list)
    {
        listPeople = list;
    }

    public People Current()
    {
        if (null == listPeople)
            return null;

        if (listPeople.Count < currentIndex)
            return null;

        return listPeople[currentIndex];
    }

    public bool MoveNext()
    {
        if (null == listPeople)
            return false;

        if (listPeople.Count > ++currentIndex)
            return true;

        return false;
    }

    public void Reset()
    {
        currentIndex = -1;
    }

}

People

public class People
{
    public string name;
    public int age;
    public bool married;
}

StudentList

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class StudentList
{
    private List list = new List();

    private People[] studentList = new People[3];

    public StudentList()
    {
        People p1 = new People()
        {
            name = "WH",
            age = 15,
            married = false
        };
        studentList[0] = p1;

        People p2 = new People()
        {
            name = "QT",
            age = 16,
            married = false
        };
        studentList[1] = p2;


        People p3 = new People()
        {
            name = "YY",
            age = 15,
            married = false
        };
        studentList[2] = p3;

        for (int i = 0; i < studentList.Length; i++)
        {
            list.Add(studentList[i]);
        }
    }

    public BaseIterator GetIterator()
    {
        return new IteratorStudent(list);
    }
}

PoliceList

using System.Collections.Generic;

public class PoliceList
{
    private List list = new List();

    public PoliceList()
    {
        People p1 = new People()
        {
            name = "WangQiang",
            age = 23,
            married = false
        };
        list.Add(p1);

        People p2 = new People()
        {
            name = "ZhangQiang",
            age = 30,
            married = true
        };
        list.Add(p2);

        People p3 = new People()
        {
            name = "LingQiang",
            age = 31,
            married = true
        };
        list.Add(p3);
    }

    public BaseIterator GetIterator()
    {
        return new IteratorPolice(list); 
    }
}

测试代码

using UnityEngine;

public class TestDDQ : MonoBehaviour
{
    void Start()
    {
        {
            PoliceList pl = new PoliceList();
            BaseIterator iterator = pl.GetIterator();

            while (iterator.MoveNext())
            {
                People p1 = iterator.Current();
                Debug.Log("姓名：" + p1.name + "   年龄：" + p1.age + "   是否结婚：" + p1.married + " ");
            }
        }

        Debug.Log("------------------------------------------------------------------");
        {
            StudentList pl = new StudentList();
            BaseIterator iterator = pl.GetIterator();

            while (iterator.MoveNext())
            {
                People p1 = iterator.Current();
                Debug.Log("姓名：" + p1.name + "   年龄：" + p1.age + "   是否结婚：" + p1.married + " ");
            }
        }
      
    }
}

结果

总结

迭代器模式统一集合查询代码，以这个为目标进现优化总结出的一个经验。

还是为了更深刻的理解设计原理和优化手段。