### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [May 31, 2021, 5:07pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/1 "2021-05-31T17:07:34Z")
Team, Below image is my sample workflow
Green - Tasks (it might have an API call, function call, or webhook)
Yellow - Wait state
In this diagram, the red color marked portion needs to be executed parallelly but among that we need path1, Path2, and Path3 to be executed in linear fashion.
T2 has to start its execution after 9 states are completed. So it has to wait for all 3 paths to complete.
**Question 1)** Is it possible to put wait ( `Workflow.sleep(some duration)` ) for 3 states at a time?
I can achieve parallel execution using Async, but using `.get` on the promise object will block my thread.
**Question 2)** Is it possible to achieve without blocking?
I tried using thenApply,handle on the promise objects but my workflow code has completed without executing this thenAppy and handle callbacks.
Awaiting your response, Thanks
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [May 31, 2021, 5:18pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/2 "2021-05-31T17:18:41Z")
> **Question 1)** Is it possible to put wait ( `Workflow.sleep(some duration)` ) for 3 states at a time?
> I can achieve parallel execution using Async, but using `.get` on the promise object will block my thread.
Yes, you can use Async to start three threads and use Workflow.sleep in each of them. Then you use Promise.allOf on the Promises returned by the Async.\<…\> function to join the threads.
> **Question 2)** Is it possible to achieve without blocking?
Yes, you can implement these branches asynchronously. You still have to block the main workflow thread as fully asynchronous workflow implementation is not supported yet.
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [May 31, 2021, 5:59pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/3 "2021-05-31T17:59:31Z")
you are referring to this way, right?
```
for(Task task : parallelFlow.getTaskList() ) {
if (task instanceof FunctionalTask) {
pilotIO.getUserData().setTask((FunctionalTask) task).setPrevResult(prevResult);
Promise promise = Async.function(runnableTask::run, pilotIO);
promiseList.add(promise);
}
}
Promise.allOf(promiseList).get();
for(Promise promise : promiseList){
System.out.println(((PilotIO) promise.get()).getUserData().getPrevResult());
}
```
I hope using `Promise.allOf(promiseList).get();` and `Promise.allOf(promiseList);` makes no difference. Correct me if i am wrong
So as you said, in this way main workflow thread will be blocked until it completes all its promises as full asynchronous workflow implementation is not supported yet.
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [May 31, 2021, 6:05pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/4 "2021-05-31T18:05:08Z")
> I hope using `Promise.allOf(promiseList).get();` and `Promise.allOf(promiseList);` makes no difference. Correct me if i am wrong
Correcting :). `Promise.allOf(promiseList)` returns a promise. So
```java
Promise.allOf(promiseList);
```
creates a promise and ignores it. So it is practically NOOP.
You want to wait on this promise to join:
```java
Promise.allOf(promiseList).get();
```
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [May 31, 2021, 6:14pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/5 "2021-05-31T18:14:44Z")
Oops, I tried both, both works fine, that’s why I came for that conclusion. Thanks for addressing this.
All other my understanding are correct?
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [May 31, 2021, 6:18pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/6 "2021-05-31T18:18:15Z")
The reason that it worked was that you didn’t need `Promise.allOf` in your case at all, as the following loop called `get` on every Promise anyway. So NOOP was fine :).
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [May 31, 2021, 6:27pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/7 "2021-05-31T18:27:38Z")
Yes, I just noticed the `promise.get()` called in the loop.
```auto
Promise.allOf(promiseList).get();
```
After the above line of code, how to get my list of values?
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [May 31, 2021, 6:29pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/8 "2021-05-31T18:29:25Z")
By calling them in the loop 🙂 and populating the result collection.
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [May 31, 2021, 6:38pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/9 "2021-05-31T18:38:06Z")
Sorry, seriously I don’t know what you’re referring to.
Like below, you want me to iterate ?
> for(Promise promise : promiseList){
> System.out.println(((PilotIO) promise.get()).getUserData().getPrevResult());
> }
I don’t know any other options. Kindly tell me how to loop it 😧
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [May 31, 2021, 6:38pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/10 "2021-05-31T18:38:34Z")
Yes, your loop code is fine. I think the cast to (PilotIO) type is unnecessary as Promise is already generic with this type.
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [May 31, 2021, 7:00pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/11 "2021-05-31T19:00:58Z")
No, my use case not solved.
It is either waits for all threads to complete or it waits for any of the threads to complete. (`allOf, anyOf`)
If you see the diagram,
I will be calling all the three tasks parallelly using `Async` which are,
1. Path1-T1
2. Path2-T1
3. Path3-T1
Say, if Path1-T1 takes 2 mins and Path2-T1 and Path3-T1 take just 3 sec to complete.
My case is after completing Path2-T1 it should call Path2Wait (5 min) and after completing Path3-T1 it should call Path3-T2.
if I use `allOf` then all my threads will wait for each other to complete.
If I use `anyOf` then my first completed thread returning its result and workflow cmpleted
If I use normal loop `.get()` on the promise object then the first `promise.get()` will block before others to continue.
@maxim kindly give your feedback!!
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [May 31, 2021, 7:28pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/12 "2021-05-31T19:28:34Z")
Don’t call individual tasks in async mode. Call each branch in async mode.
Something like:
```java
void branch1() {
activities.task11();
Workflow.sleep(Duration.ofMinutes(1));
activities.task12();
}
void branch2() {
activities.task21();
Workflow.sleep(Duration.ofMinutes(5));
activities.task22();
}
void branch3() {
activities.task31();
activities.task32();
Workflow.sleep(Duration.ofHours(2));
}
...
Promise b1 = Async.procedure(this::branch1);
Promise b2 = Async.procedure(this::branch2);
Promise b3 = Async.procedure(this::branch3);
Promise.anyOf(b1, b2, b3);
```
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [May 31, 2021, 7:42pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/13 "2021-05-31T19:42:17Z")
Thank you so much @maxim for your response,
I hope `Workflow.sleep(Duration.ofHours(2))` will not hold a thread,
will it be handled similar to the scheduler model where at a constant interval a single thread will fetch DB and process the timer which is completed?
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [May 31, 2021, 10:46pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/14 "2021-05-31T22:46:58Z")
Yes, it is not going to hold the thread. You absolutely can have more workflows waiting than your worker has threads.
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [June 1, 2021, 6:37am UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/15 "2021-06-01T06:37:04Z")
> [@maxim](#):
>
> Yes, it is not going to hold the thread. You absolutely can have more workflows waiting than your worker has threads.
Thanks for the response
When to use `.thenAppply, .handle` callbacks in promise objects.
because if we use these callbacks then the workflow has completed before executing these callbacks
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [June 1, 2021, 6:39am UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/16 "2021-06-01T06:39:50Z")
As soon as the main workflow method (annotated with @WorkflowMethod) returns workflow completes. So make sure that you block the main workflow thread until all the work of the workflow is done.
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [June 1, 2021, 6:45am UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/17 "2021-06-01T06:45:08Z")
> [@maxim](#):
>
> work of the workflow
In my context, I have to block my main workflow thread until it execute the call back of my promise object
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [June 1, 2021, 6:48am UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/18 "2021-06-01T06:48:57Z")
@maxim Is there any plan in future to implement workflow code fully asynchronous?
---
### Author:  [@maxim](https://community.temporal.io/u/maxim)
#### Post date: [June 1, 2021, 5:07pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/19 "2021-06-01T17:07:42Z")
Yes, but why do you care? It is a purely caching optimization.
---
### Author:  [@anil\_kumble](https://community.temporal.io/u/anil_kumble)
#### Post date: [June 1, 2021, 5:50pm UTC](https://community.temporal.io/t/how-to-execute-wait-state-and-tasks-parallelly-in-temporal/2281/20 "2021-06-01T17:50:20Z")
I care as it blocks a thread in my app server. It will slow down the execution right?
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