C#多例模式之限制对象个数

淩亂°似流年 2023-10-11 13:06 5阅读 0赞

## （一）题目描述 ##

最多创建三个对象，单例模式的变种

## （二）代码 ##

测试代码：

using System;
    using System.Collections;
    
    namespace MultitonLimit
    {
        class Program
        {
            static void Main(string[] args)
            {
                for(int i = 0; i < 15; i++)
                {
                    Teacher t = Teacher.getInstance();
                    Console.WriteLine(t.ToString());
                }
    
            }
            
        }
    }

Teacher类：

using System;
    using System.Collections;
    
    
    namespace MultitonLimit
    {
        class Teacher
        {
                private static int maxNumber = 3;
                private static ArrayList nameList = new ArrayList();
                private static ArrayList teacherList = new ArrayList();
                private static int currentNumber = 0;
                private static int count = 0;
    
                static Teacher()
                {
                    for (int i = 0; i < maxNumber; i++)
                    {
                        teacherList.Add(new Teacher("第" + (i + 1) + "个老师"));
                    }
                }
    
                private Teacher()
                {
    
                }
    
                private Teacher(string name)
                {
                    nameList.Add(name);
                }
    
                public static Teacher getInstance()
                {
                    count++;
                    //Random r = new Random();
                    //currentNumber = r.Next(maxNumber);
                    if (count % 3 == 0)
                    {
                        count = 0;
                     }
                    currentNumber = count;
                   // Console.Write(count);
    
                    return teacherList[currentNumber] as Teacher;
                }
    
                public override string ToString()
                {
                    return nameList[currentNumber].ToString();
                }
    
    
            
        }
    }

## （三）思路 ##

单例模式的变种，先创建对象（在此处限制数量），然后返回对象。思想类似于数据库连接池。