Notify consumers when all tasks have completed without blocking the thread

» chash » Notify consumers when all tasks have completed without blocking the thread

By : Tsugumi Winters

Date : November 24 2020, 04:01 AM

I wish this help you First off, don't use the Task constructor at all. If you want to run a delegate in a thread pool thread, use Task.Run. Next, don't use ContinueWith, use await to add continuations to tasks. It's much easier to write correct code that way, particularly with respect to proper error handling. Your code is most effectively written as:

code :

try
{
    await Task.Run(() => Execute(action));
    Continuation();    
}
catch(Exception e)
{
    LogExceptions(e)
}
finally
{
    CustomLogging();
}

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How to use SignalR to notify web clients from ASP.NET MVC 3 that MSMQ tasks were completed

By : user3782142

Date : March 29 2020, 07:55 AM

it helps some times If I understand correctly, you need a way of associating a task to a given user/client so that you can tell the client when their task has completed.
SignalR API documentation tells me you can call JS methods for specific clients based on the client id (https://github.com/SignalR/SignalR/wiki/SignalR-Client). In theory you could do something like:

code :

string clientId = processedMessage.ClientId //Stored when you originally queued it.
IConnection connection = Connection.GetConnection<ProcessNotificationsConnection>();
connection.Send(clientId, "Your data was processed");

public class MyHub : Hub
{
     public void Send(string data)
     {
     // Invoke a method on the calling client
     Caller.addMessage(data);

     // Similar to above, the more verbose way
     Clients[Context.ClientId].addMessage(data);

     // Invoke addMessage on all clients in group foo
     Clients["foo"].addMessage(data);
     }
}

Blocking tasks until previous task has completed

By : john

Date : March 29 2020, 07:55 AM

may help you . Use Task parallel library..
Task.Factory.StartNew(METHOD).ContinueWith(task => DispatcherHelper.Dispatch(() => { Mouse.OverrideCursor = null; }));

Multiple executor tasks notify master on completed?

By : Evan Johnson

Date : March 29 2020, 07:55 AM

I hope this helps . This sounds like a job of ExecutorService.invokeAll.

code :

Collection<Callable> tasks = <get all sub tasks>;
executorService.invokeAll(tasks);
// Execution proceeds at the following line only once all "tasks" have been run

for (Runnable task:tasks) {
    futures.add(executorService.submit(task));
}

for (Future<Void> result:futures) {
    result.get();
}

Consuming blocking collection with multiple tasks/consumers

By : Siew Jin Kung Lim

Date : March 29 2020, 07:55 AM

This might help you A few small things
You never called CompleteAdding, by not doing that your consuming foreach loops will never complete and hang forever. Fix that by doing users.CompleteAdding() after the initial for loop. You never wait for the work to finish, Run() will spin up your 100 threads (which likely WAY too much unless your real process involves a lot of waiting for uncontested resources). Because Tasks are not foreground threads they will not keep your program open when your Main exits. You need a CountdownEvent to track when everything is done. You don't start up your consumers till after your producer has finished all of it's work, you should spin off the producer in to a separate thread or start the consumers first so they are ready to work while you populate the producer on the main thread.

code :

class Program
{
    private const int MaxThreads = 100; //way to high for this example.
    private static readonly CountdownEvent cde = new CountdownEvent(MaxThreads);
    public static readonly BlockingCollection<User> users = new BlockingCollection<User>();

    static void Main(string[] args)
    {
        Run(); 

        for (int i = 0; i < 100000; i++)
        {
            var u = new User {Id = i, Name = "user " + i};
            users.Add(u);
        }
        users.CompleteAdding();
        cde.Wait();
    }

    static void Run()
    {
        for (int i = 0; i < MaxThreads; i++)
        {
            Task.Factory.StartNew(Process, TaskCreationOptions.LongRunning);
        }
    }

    static void Process()
    {
        foreach (var user in users.GetConsumingEnumerable())
        {
            Console.WriteLine(user.Id);
        }
        cde.Signal();
    }
}

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
}

NSURLSession notify when all tasks are completed

By : user3301023

Date : March 29 2020, 07:55 AM

it helps some times I think you need to track this yourself. Consider keeping an array of task objects. As you start a task, add the task object to the array. When the task is finished, remove the task object from the array.
When you arrive at zero tasks in the array, you are done.