坚持学习WF(6):开发可复用的宿主程序

我们之前写工作流宿主程序一般都是直接写在program.cs文件里，这样复用性比较差。我们就简单的写两个类，这两个类主要实现的是对WorkflowInstance和WorkflowRuntime的封装。我们以后的例子都会使用这两个类。

第一个类是WorkflowInstanceWrapper，代码如下：

[Serializable]
    public class WorkflowInstanceWrapper
    {
        private WorkflowInstance _workflowInstance;
        private ManualResetEvent _waitHandle = new ManualResetEvent(false);
        private Dictionary<String, Object> _outputParameters= new Dictionary
                <string, object>();
        private Exception _exception;
        private String _reasonSuspended = String.Empty;

        public WorkflowInstanceWrapper(WorkflowInstance instance)
        {
            _workflowInstance = instance;
        }        
        public Guid Id
        {
            get
            {
                if (_workflowInstance != null)
                   return _workflowInstance.InstanceId;
                else
                   return Guid.Empty;
            }
        }        
        public Dictionary<String, Object> OutputParameters
        {
            get { return _outputParameters; }
            set { _outputParameters = value; }
        }        
        public ManualResetEvent WaitHandle
        {
            get { return _waitHandle; }
            set { _waitHandle = value; }
        }        
        public Exception Exception
        {
            get { return _exception; }
            set { _exception = value; }
        }        
        public String ReasonSuspended
        {
            get { return _reasonSuspended; }
            set { _reasonSuspended = value; }
        }        
        public WorkflowInstance WorkflowInstance
        {
            get { return _workflowInstance; }
        }        
        public void StopWaiting()
        {
            _waitHandle.Set();
        }
    }
1._exception,_reasonSuspended：表示当工作流非正常终止或挂起时的相关信息。

2. OutputParameters：用来接收工作流的输出参数，工作流运行时引擎将引发 WorkflowCompleted事件。

工作流运行时引擎将在WorkflowCompletedEventArgs 中传入工作流的所有输出参数。 这些参数包括工作

流的 out 和 ref 参数。
 

第二类是WorkflowManager代码如下：  

 public class WorkflowRuntimeManager : IDisposable
    {
        private WorkflowRuntime _workflowRuntime;
        private Dictionary<Guid, WorkflowInstanceWrapper> _workflows
                               = new Dictionary<Guid, WorkflowInstanceWrapper>();
      
        public WorkflowRuntimeManager(WorkflowRuntime instance)
        {
            _workflowRuntime = instance;
            if (instance == null)
            {
                throw new NullReferenceException(
                    "A non-null WorkflowRuntime instance is required");
            }            
            SubscribeToEvents(instance);
        }

      
        public WorkflowInstanceWrapper StartWorkflow(Type workflowType,
            Dictionary<String, Object> parameters)
        {
            WorkflowInstance instance = _workflowRuntime.CreateWorkflow(
                workflowType, parameters);
            WorkflowInstanceWrapper wrapper
                = AddWorkflowInstance(instance);
            instance.Start();
            return wrapper;
        }
        
        public WorkflowInstanceWrapper StartWorkflow(String markupFileName,
            String rulesMarkupFileName,
            Dictionary<String, Object> parameters)
        {
            WorkflowInstance instance = null;
            WorkflowInstanceWrapper wrapper = null;
            XmlReader wfReader = null;
            XmlReader rulesReader = null;
            try
            {
                wfReader = XmlReader.Create(markupFileName);
                if (!String.IsNullOrEmpty(rulesMarkupFileName))
                {
                    rulesReader = XmlReader.Create(rulesMarkupFileName);
                    instance = _workflowRuntime.CreateWorkflow( wfReader, rulesReader, parameters);
                }
                else
                {
                    instance = _workflowRuntime.CreateWorkflow(wfReader, null, parameters);
                }
                wrapper = AddWorkflowInstance(instance);
                instance.Start();
            }
            finally
            {
                if (wfReader != null)
                {
                    wfReader.Close();
                }
                if (rulesReader != null)
                {
                    rulesReader.Close();
                }
            }
            return wrapper;
        }

       public WorkflowRuntime WorkflowRuntime
        {
            get { return _workflowRuntime; }
        }        
        public Dictionary<Guid, WorkflowInstanceWrapper> Workflows
        {
            get { return _workflows; }
        }        
        public event EventHandler<WorkflowLogEventArgs> MessageEvent;    

       
        public void ClearWorkflow(Guid workflowId)
        {
            if (_workflows.ContainsKey(workflowId))
            {
                _workflows.Remove(workflowId);
            }
        }
      
        public void ClearAllWorkflows()
        {
            _workflows.Clear();
        }
       
        private WorkflowInstanceWrapper AddWorkflowInstance(
            WorkflowInstance instance)
        {
            WorkflowInstanceWrapper wrapper = null;
            if (!_workflows.ContainsKey(instance.InstanceId))
            {
                wrapper = new WorkflowInstanceWrapper(instance);
                _workflows.Add(wrapper.Id, wrapper);
            }
            return wrapper;
        }
     
        public WorkflowInstanceWrapper FindWorkflowInstance(Guid workflowId)
        {
            WorkflowInstanceWrapper result = null;
            if (_workflows.ContainsKey(workflowId))
            {
                result = _workflows[workflowId];
            }
            return result;
        }
       
        public void WaitAll(Int32 msecondsTimeout)
        {
            if (_workflows.Count > 0)
            {
                WaitHandle[] handles = new WaitHandle[_workflows.Count];
                Int32 index = 0;
                foreach (WorkflowInstanceWrapper wrapper
                    in _workflows.Values)
                {
                    handles[index] = wrapper.WaitHandle;
                    index++;
                }
                WaitHandle.WaitAll(handles, msecondsTimeout, false);
            }
        }
     
        public void Dispose()
        {
            if (_workflowRuntime != null)
            {
                _workflowRuntime.StopRuntime();
                _workflowRuntime.Dispose();
            }
            ClearAllWorkflows();
        }
      
        private void SubscribeToEvents(WorkflowRuntime runtime)
        {
            runtime.Started += new EventHandler<WorkflowRuntimeEventArgs>( runtime_Started);
            runtime.Stopped += new EventHandler<WorkflowRuntimeEventArgs>(runtime_Stopped);
            runtime.WorkflowAborted+= ......
            runtime.WorkflowCompleted+= ......
            runtime.WorkflowCreated += ......   
            ............
        }

        void runtime_Started(object sender, WorkflowRuntimeEventArgs e)
        {
            LogStatus(Guid.Empty, "Started");
        }
        void runtime_Stopped(object sender, WorkflowRuntimeEventArgs e)
        {
            LogStatus(Guid.Empty, "Stopped");
        }
        void runtime_WorkflowCreated(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowCreated");
        }
        void runtime_WorkflowStarted(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowStarted");
        }
        void runtime_WorkflowIdled(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowIdled");
        }

        void runtime_WorkflowCompleted(object sender, WorkflowCompletedEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowCompleted");
            WorkflowInstanceWrapper wrapper
                = FindWorkflowInstance(e.WorkflowInstance.InstanceId);
            if (wrapper != null)
            {
                wrapper.OutputParameters = e.OutputParameters;
                wrapper.StopWaiting();
            }
        }

        void runtime_WorkflowTerminated(object sender,
            WorkflowTerminatedEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowTerminated");
            WorkflowInstanceWrapper wrapper = FindWorkflowInstance(e.WorkflowInstance.InstanceId);
            if (wrapper != null)
            {
                wrapper.Exception = e.Exception;
                wrapper.StopWaiting();
            }
        }

        void runtime_WorkflowSuspended(object sender, WorkflowSuspendedEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowSuspended");
            WorkflowInstanceWrapper wrapper = FindWorkflowInstance(e.WorkflowInstance.InstanceId);
            if (wrapper != null)
            {
                wrapper.ReasonSuspended = e.Error;
            }
        }

        void runtime_WorkflowResumed(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowResumed");
        }
        void runtime_WorkflowPersisted(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowPersisted");
        }
        void runtime_WorkflowLoaded(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowLoaded");
        }
        void runtime_WorkflowAborted(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowAborted");
            WorkflowInstanceWrapper wrapper
                = FindWorkflowInstance(e.WorkflowInstance.InstanceId);
            if (wrapper != null)
            {
                wrapper.StopWaiting();
            }
        }

        void runtime_WorkflowUnloaded(object sender, WorkflowEventArgs e)
        {
            LogStatus(e.WorkflowInstance.InstanceId, "WorkflowUnloaded");
        }

        private void LogStatus(Guid instanceId, String msg)
        {
            if (MessageEvent != null)
            {
                String formattedMsg;
                if (instanceId == Guid.Empty)
                {
                    formattedMsg = String.Format("Runtime - {0}", msg);
                }
                else
                {
                    formattedMsg = String.Format("{0} - {1}", instanceId, msg);
                }
                //raise the event
                MessageEvent(this, new WorkflowLogEventArgs(formattedMsg));
            }
        }

    }   
    public class WorkflowLogEventArgs : EventArgs
    {
        private String _msg = String.Empty;
        public WorkflowLogEventArgs(String msg)
        {
            _msg = msg;
        }

        public String Message
        {
            get { return _msg; }
        }

1._workflows:一个key为Guid，value为WorkflowInstanceWrapper的字典。
2.SubscribeToEvent()：给workflowRuntime订阅事件.
3.StartWorkflow（）：实现创建，开始工作流.
4.MessageEvent：对Message进行格式化。
5.WaitAll（）用来挂起当前的线程直到所有的workflows完成，每个WorkflowInstanceWrapper有一个WaitHandle属性以便宿主程序能灵活控制。 

下面是测试代码：
using (WorkflowRuntimeManager manager
        = new WorkflowRuntimeManager(new WorkflowRuntime("WorkflowRuntime")))
{
   manager.MessageEvent += delegate(Object sender, WorkflowLogEventArgs e)
   {
      Console.WriteLine(e.Message);
   };
   manager.WorkflowRuntime.StartRuntime();
   Dictionary<String, Object> wfArguments= new Dictionary<string, object>();
   wfArguments.Add("InputString", "one");
   WorkflowInstanceWrapper instance = manager.StartWorkflow(
           typeof(SharedWorkflows.Workflow1), wfArguments);
   instance.WorkflowInstance.Terminate("Manually terminated");
   instance.WaitHandle.WaitOne(10000, false);
   foreach (WorkflowInstanceWrapper wrapperin manager.Workflows.Values)
   {
       if (wrapper.OutputParameters.ContainsKey("Result"))
       {
            Console.WriteLine(wrapper.OutputParameters["Result"]);
       }
       if (wrapper.Exception != null)
       {
     Console.WriteLine("{0}-Exception:{1}",wrapper.Id,wrapper.Exception.Message);
       }
       if (wrapper.ReasonSuspended.Length > 0)
       {
    Console.WriteLine("{0}-Suspended: {1}",wrapper.Id, wrapper.ReasonSuspended);
       }
}    manager.ClearAllWorkflows();






















下面运行结果，从该结果可以清晰的看出工作流的执行过程：


 

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