前言

在.net4.0以后异步操作,并行计算变得异常简单,但是由于公司项目开发基于.net3.5所以无法用到4.0的并行计算以及Task等异步编程。因此,为了以后更方便的进行异步方式的开发,我封装实现了异步编程框架,通过BeginInvoke、EndInvoke的方式实现异步编程。

框架结构

整个框架包括四个部分

1. 基类抽象Opeartor
   异步操作的基类，实现了异步操作接口
2. FuncAsync
   异步的Func
3. ActionAsync
   异步的Action

4. Asynchorus
   对ActionAsync和FuncAsync的封装

   Operator

   Operator是一个抽象类,实现了IOperationAsync和IContinueWithAsync两个接口。
   IOperationAsync实现了异步操作,IContinueWithAsync实现了类似于Task的ContinueWith方法,在当前异步操作完成后继续进行的操作

   IOperationAsync接口详解

   public interface IOperationAsync
   {
       IAsyncResult Invoke();
       void Wait();
       void CompletedCallBack(IAsyncResult ar);
       void CatchException(Exception exception);
   }

• Invoke():异步方法的调用
• Wait():等待异步操作执行
• CompletedCallBack():操作完成回调
• CatchException():抓取异常

IContinueWithAsync接口详情

public interface IContinueWithAsync
{
    Operator Previous { get; set; }
    Operator Next { get; set; }
    Operator ContinueWithAsync(Action action);
    Operator ContinueWithAsync<TParameter>(Action<TParameter> action, TParameter parameter);
}

• Previous:前一个操作
• Next:下一个操作
• ContinueWithAsync():异步继续操作

public abstract class Operator : IOperationAsync, IContinueWithAsync
{
    public IAsyncResult Middle;
    public readonly string Id;
    public Exception Exception { get; private set; }
    public Operator Previous { get; set; }
    public Operator Next { get; set; }
    protected Operator()
    {
        Id = Guid.NewGuid().ToString();
    }
    public abstract IAsyncResult Invoke();
    protected void SetAsyncResult(IAsyncResult result)
    {
        this.Middle = result;
    }
    public virtual void Wait()
    {
        if (!Middle.IsCompleted) Middle.AsyncWaitHandle.WaitOne();
    }
    public virtual void CompletedCallBack(IAsyncResult ar)
    {
    }
    public void CatchException(Exception exception)
    {
        this.Exception = exception;
    }
    protected Operator ContinueAsync()
    {
        if (Next != null) Next.Invoke();
        return Next;
    }
    public virtual Operator ContinueWithAsync(Action action)
    {
        Next = new ActionAsync(action);
        Next.Previous = this;
        return Next;
    }
    public virtual Operator ContinueWithAsync<TParameter>(Action<TParameter> action, TParameter parameter)
    {
        Next = new ActionAsync<TParameter>(action, parameter);
        Next.Previous = this;
        return Next;
    }
    public virtual Operator ContinueWithAsync<TResult>(Func<TResult> func)
    {
        Next = new FuncAsync<TResult>();
        Next.Previous = this;
        return Next;
    }
    public virtual Operator ContinueWithAsync<TParameter, TResult>(Func<TParameter, TResult> func,
        TParameter parameter)
    {
        Next = new FuncAsync<TParameter, TResult>(func, parameter);
        Next.Previous = this;
        return Next;
    }
}

无返回异步操作

ActionAsync

public class ActionAsync : Operator
{
    private readonly Action _action;
    protected ActionAsync()
    {
    }
    public ActionAsync(Action action)
        : this()
    {
        this._action = action;
    }
    public override IAsyncResult Invoke()
    {
        var middle = _action.BeginInvoke(CompletedCallBack, null);
        SetAsyncResult(middle);
        return middle;
    }
    public override void CompletedCallBack(IAsyncResult ar)
    {
        try
        {
            _action.EndInvoke(ar);
        }
        catch (Exception exception)
        {
            this.CatchException(exception);
        }
        ContinueAsync();
    }
}
public class ActionAsync<T> : ActionAsync
{
    public T Result;
    private readonly Action<T> _action1;
    protected readonly T Parameter1;
    public ActionAsync()
    {
    }
    public ActionAsync(T parameter)
    {
        this.Parameter1 = parameter;
    }
    public ActionAsync(Action<T> action, T parameter)
    {
        this._action1 = action;
        this.Parameter1 = parameter;
    }
    public override IAsyncResult Invoke()
    {
        var result = _action1.BeginInvoke(Parameter1, CompletedCallBack, null);
        SetAsyncResult(result);
        return result;
    }
    public override void CompletedCallBack(IAsyncResult ar)
    {
        try
        {
            _action1.EndInvoke(ar);
        }
        catch (Exception exception)
        {
            this.CatchException(exception);
        }
        ContinueAsync();
    }
}

有返回异步

FuncAsync实现了IFuncOperationAsync接口

IFuncOperationAsync

public interface IFuncOperationAsync<T>
{
    void SetResult(T result);
    T GetResult();
}

• SetResult(T result):异步操作完成设置返回值

• GetResult():获取返回值

  FuncAsync

  public class FuncAsync<TResult> : Operator, IFuncOperationAsync<TResult>
  {
  private TResult _result;
  
  public TResult Result
  {
      get
      {
          if (!Middle.IsCompleted || _result == null)
          {
              _result = GetResult();
          }
          return _result;
      }
  }
  private readonly Func<TResult> _func1;
  public FuncAsync()
  {
  }
  public FuncAsync(Func<TResult> func)
  {
      this._func1 = func;
  }
  public override IAsyncResult Invoke()
  {
      var result = _func1.BeginInvoke(CompletedCallBack, null);
      SetAsyncResult(result);
      return result;
  }
  public override void CompletedCallBack(IAsyncResult ar)
  {
      try
      {
          var result = _func1.EndInvoke(ar);
          SetResult(result);
      }
      catch (Exception exception)
      {
          this.CatchException(exception);
          SetResult(default(TResult));
      }
      ContinueAsync();
  }
  public virtual TResult GetResult()
  {
      Wait();
      return this._result;
  }
  public void SetResult(TResult result)
  {
      _result = result;
  }
  }
  public class FuncAsync<T1, TResult> : FuncAsync<TResult>
  {
  protected readonly T1 Parameter1;
  private readonly Func<T1, TResult> _func2;
  public FuncAsync(Func<T1, TResult> action, T1 parameter1)
      : this(parameter1)
  {
      this._func2 = action;
  }
  protected FuncAsync(T1 parameter1)
      : base()
  {
      this.Parameter1 = parameter1;
  }
  public override IAsyncResult Invoke()
  {
      var result = _func2.BeginInvoke(Parameter1, CompletedCallBack, null);
      SetAsyncResult(result);
      return result;
  }
  public override void CompletedCallBack(IAsyncResult ar)
  {
      try
      {
          var result = _func2.EndInvoke(ar);
          SetResult(result);
      }
      catch (Exception exception)
      {
          CatchException(exception);
          SetResult(default(TResult));
      }
      ContinueAsync();
  }
  }

  Asynchronous 异步操作封装

  ActionAsync和FuncAsync为异步操作打下了基础,接下来最重要的工作就是通过这两个类执行我们的异步操作,为此我封装了一个异步操作类
  主要封装了以下几个部分：

1. WaitAll(IEnumerable<Operator> operations):等待所有操作执行完毕
2. WaitAny(IEnumerable<Operator> operations):等待任意操作执行完毕
3. ActionAsync
4. FuncAsync
5. ContinueWithAction

6. ContinueWithFunc

   后面四个包含若干个重载,这里只是笼统的代表一个类型的方法

   WaitAll

   public static void WaitAll(IEnumerable<Operator> operations)
   {
   foreach (var @operator in operations)
   {
       @operator.Wait();
   }
   }

   WaitAny

   public static void WaitAny(IEnumerable<Operator> operations)
   {
   while (operations.All(o => !o.Middle.IsCompleted))
       Thread.Sleep(100);
   }

   等待时间可以自定义

   ActionInvoke

   public static Operator Invoke(Action action)
   {
   Operator operation = new ActionAsync(action);
   operation.Invoke();
   return operation;
   }
   public static Operator Invoke<T>(Action<T> action, T parameter)
   {
   Operator operation = new ActionAsync<T>(action, parameter);
   operation.Invoke();
   return operation;
   }
   public static Operator Invoke<T1, T2>(Action<T1, T2> action, T1 parameter1, T2 parameter2)
   {
   Operator operation = new ActionAsync<T1, T2>(action, parameter1, parameter2);
   operation.Invoke();
   return operation;
   }

   FuncInvoke

   public static Operator Invoke<TResult>(Func<TResult> func)
   {
   Operator operation = new FuncAsync<TResult>(func);
   operation.Invoke();
   return operation;
   }
   public static Operator Invoke<TParameter, TResult>(Func<TParameter, TResult> func, TParameter parameter)
   {
   TParameter param = parameter;
   Operator operation = new FuncAsync<TParameter, TResult>(func, param);
   operation.Invoke();
   return operation;
   }
   public static Operator Invoke<T1, T2, TResult>(Func<T1, T2, TResult> func, T1 parameter1, T2 parameter2)
   {
   Operator operation = new FuncAsync<T1, T2, TResult>(func, parameter1, parameter2);
   operation.Invoke();
   return operation;
   }

   ContinueWithAction

   public static Operator ContinueWithAsync(IEnumerable<Operator>operators, Action action)
   {
   return Invoke(WaitAll, operators)
       .ContinueWithAsync(action);
   }
   public static Operator ContinueWithAsync<TParameter>(IEnumerable<Operator> operators, Action<TParameter> action, TParameter parameter)
   {
   return Invoke(WaitAll, operators)
       .ContinueWithAsync(action, parameter);
   }

   ContinueWithFunc

   public static Operator ContinueWithAsync<TResult>(IEnumerable<Operator> operators,Func<TResult> func)
   {
   return Invoke(WaitAll, operators)
       .ContinueWithAsync(func);
   }
   public static Operator ContinueWithAsync<TParameter, TResult>(IEnumerable<Operator> operators, 
   Func<TParameter, TResult> func, TParameter parameter)
   {
   return Invoke(WaitAll, operators)
       .ContinueWithAsync(func, parameter);
   }

   这里有个bug当调用ContinueWithAsync后无法调用Wait等待,本来Wait需要从前往后等待每个异步操作,但是测试了下不符合预期结果。不过理论上来说应该无需这样操作,ContinueWithAsync只是为了当上一个异步操作执行完毕时继续执行的异步操作,若要等待,那不如两个操作放到一起,最后再等待依然可以实现。

前面的都是单步异步操作的调用,若需要对某集合进行某个方法的异步操作,可以foreach遍历

public void ForeachAsync(IEnumerbale<string> parameters)
{
    foreach(string p in parameters)
    {
        Asynchronous.Invoke(Tast,p);
    }
}
public void Test(string parameter)
{
    //TODO:做一些事
}

每次都需要去手写foreach,比较麻烦,因此实现类似于PLinq的并行计算方法实在有必要,不过有一点差别,PLinq是采用多核CPU进行并行计算,而我封装的仅仅遍历集合进行异步操作而已

ForeachAction

public static IEnumerable<Operator> Foreach<TParameter>(IEnumerable<TParameter> items, Action<TParameter> action)
{
    return items.Select(t => Invoke(action, t)).ToList();
}

ForeachFunc

public static IEnumerable<Operator> Foreach<TParameter, TResult>(IEnumerable<TParameter> items, Func<TParameter, TResult> func)
{
    return items.Select(parameter => Invoke(func, parameter)).ToList();
}

如何使用

• 无返回值异步方法调用

  public void DoSomeThing()
  {
  //TODO:
  }

  通过Asynchronous.Invoke(DoSomeThing) 执行

  public void DoSomeThing(string parameter)
  {
  //TODO:
  }

  通过Asynchronous.Invoke(DoSomeThing,parameter) 执行

• 有返回值异步方法调用

  public string DoSomeThing()
  {
  //TODO:
  }

  通过Asynchronous.Invoke(()=>DoSomeThing())执行

  public string DoSomeThing(string parameter)
  {
  //TODO:
  }

  通过Asynchronous.Invoke(()=>DoSomeThing(parameter))执行,或者也可以传入参数通过Asynchronous.Invoke(p=>DoSomeThing(p),parameter)

• 无返回值Foreach

  public void Test
  {
  int[] parameters = {1,2,3,4,5};
  Asynchronous.Foreach(parameters,Console.WriteLine);
  }

• 有返回值Foreach

  public void Test
  {
  int[] parameters = {1,2,3,4,5};
  var operators = Asynchronous.Foreach(parameters,p=> p*2);
  Asynchrous.WaitAll(operators);
  Asynchronous.Foreach(operators.Cast<FuncAsync<int,int>>(),
      p=> Console.WriteLine(p.Result));
  }

  首先将集合每个值扩大2倍,然后输出

• 异步执行完再执行

  public void Test
  {
  int[] parameters = {1,2,3,4,5};
  var operators = Asynchronous.Foreach(parameters,p=> p*2);
  Asynchrous.ContinueWithAsync(operators,Console.WriteLine,"执行完成");
  }

• 每次执行完继续执行
  可能有时候我们需要遍历一个集合,每个元素处理完成后我们需要输出XX处理完成

  public void Test
  {
  int[] parameters = {1,2,3,4,5};
  var operators = Asynchronous.Foreach(parameters,p=> p*2);
  Asynchronous.Foreach(operators,o=>{
      o.ContinueWithAsync(()={
          //每个元素执行完时执行
          if(o.Exception != null)
          {
              //之前执行时产生未处理的异常,这里可以捕获到  
          }
      });
  });
  }

• 可以实现链式异步操作

  public void Chain()
  {
  Asynchronous.Invoke(Console.WriteLine,1)
  .ContinueWithAsync(Console.WriteLine,2)
  .ContinueWithAsync(Console.WriteLine,3)
  }

  这样会按步骤输出1,2,3

  结束语

  以上只是列出了部分重载方法,其他重载方法无非就是加参数,本质实际是一样的,具体可以已提交至github。我还封装了for方法,但是感觉没什么用,而且也从没有用到过,这里不再提
  通过以上的封装,已经能完成日常大部分的操作,调用还是比较方便的。

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