singleton示例代码

 

实现singleton基础代码：

    public class singleton
    {
        private static singleton instance;

        private singleton() { }

        public static singleton instance
        {
            get
            {
                if (instance == null)
                {
                    instance = new singleton();
                }
                return instance;
            }
        }
    }

 

DOUBLE CHECK避免多线程同时产生对象：

 

 1  public class singleton
 2     {
 3         private static volatile singleton instance = null;
 4 
 5         private static object lockHelper = new object();
 6 
 7         private singleton() { }
 8 
 9         public static singleton instance
10         {
11             get
12             {
13                 if (instance == null)
14                 {                       //当多线程同时到达此处，检查instance为null,会同时产生实例.
15                     lock (lockHelper)
16                     {
17                         if (instance == null)
18                         {
19                             instance = new singleton();
20                         }
21                     }
22                 }
23                 return instance;
24             }
25         }
26     }

 

简捷的代码实现double check的效果：弊端在于无法传递参数

 

 1    class Singleton     //最简捷的代码,实现double check效果的singleton
 2     {
 3         public static readonly Singleton instance = new Singleton();
 4         private Singleton() { }
 5     }
 6 
 7     class Singleton     //上例中的代码展开的写法
 8     {
 9         public static readonly Singleton instance;
10 
11         static Singleton()
12         {
13             instance = new Singleton();
14         }
15 
16         private Singleton() { }
17     }

 

传递参数的：

 1     public class singleton
 2     {
 3         private static singleton instance;
 4 
 5         private singleton(int x,int y)
 6         {
 7             this.x = x;
 8             this.y = y;
 9         }
10 
11         public static singleton GETinstance
12         {
13             get
14             {
15                 if (instance == null)
16                 {
17                       instance = new singleton(x,y);
18                 }
19                 return instance;
20             }
21             int x;
22             int y;
23         }
24     }
25 

 

static menthod get singleton :

        public static singleton GETinstance
        {
            get
            {
                if (instance == null)
                {
                      instance = new singleton(x,y);
                }
                return instance;
            }
            int x;
            int y;
        }
    }

    class Singleton     //最简捷的代码,实现double check效果的singleton
    {
        public static readonly Singleton instance = new Singleton();
        private Singleton() { }

        public int x
        {
            get 
            {
                return this.x;
            }
            set
            {
                this.x = x;
            }
        }

        public int y
        {
            get 
            {
                return this.y;
            }
            set
            {
                this.y = y;
            }
            int x;
            int y;
        }
    }

调用方法：

 

    class test
    {
        public static void Main()
        {
            Singleton instance = Singleton.instance();
            instance.x = 100;
            instance.y = 200;
            Console.WriteLine(instance);
        }
    }

 

 

我考。。终于写完啦。。。