Workflow is very powerful but I felt crippled without the Unity Container that I've come to depend on heavily in any application, no matter how large or small. Case in point a new utility I'm working on to convert HTML to MAML so that I can take advantage of Sandcastles Help File Builder's ConceptualContent which consist of MAML formated help files (no HTML). Workflow seems optimal for this purpose. The first requirement is (was) to plug in a Unity Container.
Workflow does offer the ability to register services that can be accessed from within activities, all that is required is to set an ExternalDataExchange attribute on your interface:
[ExternalDataExchange]
public interface IWFState<T>
{
T Data { get; set; }
IUnityContainer UnityContainer { get; set; }
ILoggerFacade Logger { get; set; }
void WireupActivity(Activity activity);
}
Then you load the service
public IWFState<T> State
{
get { return _state; }
set
{
_state = value;
OnStateSet();
}
}
/// <summary>
/// Loads the local services.
/// </summary>
public virtual void LoadLocalServices()
{
ExternalDataExchangeService localServices =
new ExternalDataExchangeService();
AddService(localServices);
localServices.AddService(State);
}
However, this requires a redundant registration process (since I've already registered services with Unity). I decided to use Unity as a trojan horse; I'll load one service, my state object which contains my UnityContainer, and then use my existing services via a UnityContainer property. Important note: some activities, i.e., Replicator and While will have to serialize referenced objects; any interfaces that Unity has to resolve in these activities will have to have [Serializable] attributes;
This permits my Activity to look as follows (ActivityBase has a UnityContainer property that returns State.UnityContainer):
namespace MAMLConvert.Activities.Logger
{
/// <summary>
/// Debug Logger
/// </summary>
public partial class LoggerDebugActivity : ActivityBase
{
public LoggerDebugActivity()
{
InitializeComponent();
}
protected override ActivityExecutionStatus
Execute(ActivityExecutionContext executionContext)
{
UnityContainer.Resolve<ILoggerFacade>().Log(
"Logging via Unity in the Activity!",
Category.Debug, Priority.None);
return base.Execute(executionContext);
}
}
}
/// <summary>
/// Tests the workflow base ensure args is set on empty constructor.
/// </summary>
[TestMethod]
public void TestMAMLWorkflowBaseStartsAssignedWorkflow()
{
using (MAMLWorkflowRuntime wfrt = new MAMLWorkflowRuntime())
{
Assert.IsNotNull(wfrt.Container);
Assert.IsTrue(wfrt.Args.Count > 0,
"Should contain at least a UnityContainer");
Assert.AreEqual("Initialized", wfrt.State.Data.MockInfo);
Assert.AreEqual(wfrt.State.Logger.GetType().FullName,
MockContainer.Resolve<ILoggerFacade>().GetType().FullName);
wfrt.Start(typeof(HtmlToMAML));
}
}
The above unit test yields the following results:
Debug(None): !! ACTIVITY WIREUP loggerDebug
Debug(None): !! ACTIVITY WIREUP loggerTrace
Debug(None): !! ACTIVITY WIREUP loggerMessageBox
Debug(None): !! ACTIVITY WIREUP loggerEmail
Debug(None): !! ACTIVITY WIREUP Logger
Debug(None): ==> Logger STATUS CHANGE - Status: Executing Result: None
Debug(None): ==> Logger EXECUTING:
Debug(None): ==> loggerDebug STATUS CHANGE - Status: Executing Result: None
Debug(None): ==> loggerDebug EXECUTING:
Debug(None): Logging via Unity in the Activity!
Debug(None): ==> loggerDebug STATUS CHANGE - Status: Closed Result: Succeeded
Debug(None): ==> loggerDebug CLOSED:
Debug(None): ==> Logger STATUS CHANGE - Status: Closed Result: Succeeded
Debug(None): ==> Logger CLOSED:
Source code available at http://www.CodePlex.com/MAMLConverter
Tags:
maml,
unity,
workflow
Categories:
MAML |
Unity |
Workflow