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<T>

cs 复制代码

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

    // 下一个
    bool MoveNext();

    // 重新开始
    void Reset();
}

IteratorPolice

cs 复制代码

using System.Collections.Generic;

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

    IteratorPolice() { }
    public IteratorPolice(List<People> 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

cs 复制代码

using System.Collections.Generic;

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

    IteratorStudent() { }
    public IteratorStudent(List<People> 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

cs 复制代码

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

StudentList

cs 复制代码

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

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

    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<People> GetIterator()
    {
        return new IteratorStudent(list);
    }
}

PoliceList

cs 复制代码

using System.Collections.Generic;

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

    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<People> GetIterator()
    {
        return new IteratorPolice(list); 
    }
}

测试代码

cs 复制代码

using UnityEngine;

public class TestDDQ : MonoBehaviour
{
    void Start()
    {
        {
            PoliceList pl = new PoliceList();
            BaseIterator<People> 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<People> 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。