opaque marsh
So i have this code:
ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
service.submit(() -> System.out.println("test"));
I submitted a runnable and it run on my PC, but when i run it on a server, it didn't, it run actually but with 50 seconds of delay which is something that i don't expect to happen. Any idea why won't the ExecutorService run the submitted task directly?
toxic briar
i've never tried using ScheduledExecutorService, but bukkit/spigot provide a BukkitScheduler, would you be able to use it instead? it works as expected every time i've used it
opaque marsh
i wanted to but the issue about it is the racing condition,
daring tree
What are you trying to do?
opaque marsh
i want to do async in one single thread
daring tree
If you’re trying to emulate a race condition then that’s the wrong way
You’d use a semaphore
opaque marsh
i don't understand
daring tree
If it’s a normal thread executor
Use the Executors::newSingleThreadedExecutor
Usually we don’t use Scheduler executor services to run tasks
opaque marsh
i needed it to be a scheduled tho cause i also use the service to schedule repeating task
daring tree
You usually delegate it to a cached thread pool
You don’t need it
You should have 1 scheduled executor service which schedules a task to be executed on another executor service
opaque marsh
wouldn't it stack the task if the main executor is busy and the scheduled keep submitting tasks and not waiting till the main executor ready?
daring tree
wut
Which one is the main executor here
And no not really
I mean sure it uses a synchronous queue for the tasks
However
There’s more than one thread picking of said queue
If it’s a cached thread pool
Then it’ll in principle consume the queue rather immediately
opaque marsh
but the cached thread pool won't synchronize the running tasks r8? cause thats what bukkit async task executor use
daring tree
Yes
So in that case use a single threaded executor service
It can be a daemon thread
And ofc if u use a single threaded one the tasks are gonna get blocked meaning
Only one task at a time will be executing as code runs linearly in response to a thread
opaque marsh
its ok, i'm doing db actions on that thread, and i wanted it to be synchronized
daring tree
I mean
You could use a locking implementation
Altho for the time being a single threaded executor service might be simpler
Anyways I suggest taking a look at ReentrantLock, ReentrantReadWriteLock and StampedLock as well as synchronized keyword
opaque marsh
would you recommend to use daemon thread for task such as modifying the database?