Java asynchronous method execution

Question

I am facing a scenario where I have to call a service method ( which involves queries execution ) repeatedly for the given list of paramers - a collection.

List<?> getResuls(List<String> params) {
   List<?> results = new ArrayList<>();
   // For every value in param call myMethod
   params.forEach( param -> 
       results.add(myMethod ( param )));
   return results;
}

myMethod (String s) { 
  // has series of queries execution based on 
  // different conditions and returns an object
  // Involves HQL
 }

Please ignore syntax errors .

The more the number of call more is the execution time.

Is there way that I can execute myMethod () calls in parallel and obtain a result when all the method calls complete.?

I skimmed through few blogs about CompletableFuture but not sure will it help my scenario.

Any suggestion would be more helpful.

Answer 1

I'm not sure if parallelStream is what you're looking for here...you can also do this:

ForkJoinPool forkJoinPool = new ForkJoinPool(processCount//2 maybe);
forkJoinPool.submit(() -> {
    youList.parallelStream().forEach {
        //add your results to another list?
        results.add(myMethod ( param )));
    };
}).join();

return results;