converting completeable future - spring-boot

Question

I'm new on completeable-future field. Anyway I have this basic JPA application I want to use async call. But I don't want the service return into completable future.
This one works fine, but..
#Async
#Cacheable(value="distributors")
public CompletableFuture<Iterable<Distributors>> getAllDistributorsAsyncCaching() throws ExecutionException, InterruptedException {
Iterable<Distributors> result = distributorsRepository.findAll();
return CompletableFuture.completedFuture(result);
}
What I want the function to return just the iterable:
#Async
#Cacheable(value="distributors")
public Iterable<Distributors> getAllDistributorsAsyncCaching() throws ExecutionException, InterruptedException {
Iterable<Distributors> result = distributorsRepository.findAll();
return CompletableFuture.completedFuture(result);
}
I have tried with completeablefuture.get() but the problem is it becomes slow,
then I tried with completeablefuture.complete() it gives me complete(Iterable) in CompleteableFuture cannot be applied to ().
Thanks in advance!

Answer 1

You can put #Async on your repository method :
public interface FooRepository extends JpaRepository<Foo, Long> {
#Async
#Query("select f from Foo f")
CompletableFuture<List<Foo>> findAllFoos();
}
Then in your service you call it with :
#Service
public class FooService {
#Autowired
private FooRepository fooRepository;
public List<Foo> getFoos() {
CompletableFuture<List<Foo>> futureFoos = fooRepository.findAllFoos();
List<Foo> foos = null;
try {
foos = futureFoos.get();
} catch (InterruptedException | ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return foos;
}
}
Here is my test (i use h2 in-memory database) :
#RunWith(SpringRunner.class)
#SpringBootTest
public class FooTests {
#Autowired
private FooRepository fooRepository;
#Autowired
private FooService fooService;
#Before
public void setUp() {
for (int i = 0; i < 100000; i++) {
Foo foo = new Foo();
foo.setId(Long.valueOf(i));
foo.setName("foo" + i);
fooRepository.save(foo);
}
}
#Test
public void test() {
System.out.println(fooService.getFoos().size());
}
}
You can put #Cacheable on service method (here is getFoos)