Possible alternative to cron job based schedulers

We are processing data sets(aka item) from database in multiple Java micro services. We get a task which has all these items. Our services process these items as kafka event. One item is one event between services.

Each service performs a said logic on the items. In one particular service, the logic is waiting for all items to get consumed and then trigger a business logic through a cron job based scheduler.

How can I remove this scheduler and maybe implement something more async in place?

I came up with the approach of creating a producer that creates an event signifying the consumption of all items for a task so that the logic can follow. Any more ideas?

Your idea is good. I assume that you create an event upon when all items are consumed and send it through some queue (or Kafka topic) where your service listens. I think this is very good and sound solution <br>
However, I am not sure what type of other ideas you are looking for.

1. One option would be to use Quartz enterprise Job scheduler
2. The other one is similar to Cron scheduler that Spring provides, but it is more humanly readable compare to corn expression. It comes with Open Source MgntUtils library written and maintained by me. Here is Javadoc page that describes the idea. The library can be obtained as a maven artifact, or on GitHub, with source code and Javadoc. Also source code includes working runnable out of the box example on how to use it. (See class com.mgnt.lifecycle.management.backgroundrunner.example.BackgroundRunnerUsageExample)

You could try creating a KTable in Kafka Streams API and implement a Punctuator that'll iterate the table and process all events it has seen

What about org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler?

Runnable task = createRunnable(s2);
ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
scheduler.initialize();
scheduler.setPoolSize(2);
scheduler.schedule(task, date);