Suppose that you have a list of item (id list referring to a table, url list to fetch page data from internet, customer keys for location query from a map service etc...). And you will start some parallel tasks for those ids. But you don't want to wait no longer than your threshold. Also you want to collect the data from the returned "CompletableFutures" which are not timed out.
How can you achieve this while using a CompletableFuture ?
PS: There is no .orTimeout () option in Java 8. It is included in Java10. And other option is using .get(N, TimeUnit.SECONDS) but it will not gave you what you want.
Outputs :
pool-1-thread-1 - - > will sleep for secs :0
Duration here = 233
pool-1-thread-2 - - > will sleep for secs :1000
pool-1-thread-3 - - > will sleep for secs :2000
pool-1-thread-4 - - > will sleep for secs :3000
pool-1-thread-5 - - > will sleep for secs :4000
pool-1-thread-6 - - > will sleep for secs :5000
Collected Results = [0, 1000, 2000, 3000, 4000, 5000, null, null, null, null]
Total Duration = 5235
How did i come here :) See below code pls
In this example your main thread will be waiting 2 seconds for each uncompleted future.
I guess N*2 seconds waiting is not the thing that you expect to see here
And yes.. There is 20 seconds duration job and it is cancelled You have a minimal gain at that point but ! But if you would have 20 tasks ...The picture would be very nagative again .
In this example your main thread will be waiting 2 seconds for each uncompleted future.
I guess N*2 seconds waiting is not the thing that you expect to see here
And yes.. There is 20 seconds duration job and it is cancelled You have a minimal gain at that point but ! But if you would have 20 tasks ...The picture would be very nagative again .
Outputs :
ForkJoinPool.commonPool-worker-1 - - > will sleep : 0ForkJoinPool.commonPool-worker-5 - - > will sleep : 4
ForkJoinPool.commonPool-worker-3 - - > will sleep : 2
ForkJoinPool.commonPool-worker-4 - - > will sleep : 3
ForkJoinPool.commonPool-worker-7 - - > will sleep : 6
ForkJoinPool.commonPool-worker-1 - - > will sleep : 5
ForkJoinPool.commonPool-worker-2 - - > will sleep : 1
ForkJoinPool.commonPool-worker-6 - - > will sleep : 7
Tasks are created here, duration = 79
Getting results
Getting results
Getting results
ForkJoinPool.commonPool-worker-2 - - > will sleep : 8
Getting results
ForkJoinPool.commonPool-worker-3 - - > will sleep : 9
Getting results
ForkJoinPool.commonPool-worker-4 - - > will sleep : 20
Getting results
Getting results
Getting results
Getting results
Getting results
Getting results
Total duration = 13080
CollectedResults = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, java.util.concurrent.TimeoutException]
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