基于静态Singleton模式的使用介绍

什么是静态单例模式？

静态单例模式（static singleton pattern）是我在实践中总结的模式，主要解决的问题是在预先知道某依赖项为单例应用时，通过静态缓存该依赖项来提供访问。当然，解决该问题的办法有很多，这只是其中一个。

实现细节

/// <summary>
  /// 静态单例
  /// </summary>
  /// <typeparam name="tclass">单例类型</typeparam>
  public static class singleton<tclass> where tclass : class, new()
  {
    private static readonly object _lock = new object();
    private static tclass _instance = default(tclass);

    /// <summary>
    /// 获取单例实例
    /// </summary>
    public static tclass getinstance()
    {
      return instance;
    }

    /// <summary>
    /// 单例实例
    /// </summary>
    public static tclass instance
    {
      get
      {
        if (_instance == null)
        {
          lock (_lock)
          {
            if (_instance == null)
            {
              _instance = new tclass(); // must be public constructor
            }
          }
        }

        return _instance;
      }
    }

    /// <summary>
    /// 设置单例实例
    /// </summary>
    /// <param name="instance">单例实例</param>
    public static void set(tclass instance)
    {
      lock (_lock)
      {
        _instance = instance;
      }
    }

    /// <summary>
    /// 重置单例实例
    /// </summary>
    public static void reset()
    {
      lock (_lock)
      {
        _instance = default(tclass);
      }
    }
  }

应用测试

class program
  {
    interface iinterfacea
    {
      string getdata();
    }
    class classa : iinterfacea
    {
      public string getdata()
      {
        return string.format("this is from classa with hash [{0}].", this.gethashcode());
      }
    }
    static void main(string[] args)
    {
      string data1 = singleton<classa>.getinstance().getdata();
      console.writeline(data1);
      string data2 = singleton<classa>.getinstance().getdata();
      console.writeline(data2);

      console.readkey();
    }
  }

测试结果