Package org.jetbrains.annotations

Annotation Type NonBlockingExecutor

@Documented
@Retention(CLASS)
@Target({TYPE,TYPE_USE})
public @interface NonBlockingExecutor

Indicates that the annotated executor (CoroutineContext, Scheduler) does not allow blocking methods execution.

If a given executor allows blocking calls, BlockingExecutor should be used.

Example 1 (Kotlin coroutines):

  class NonBlockingExampleService {
      val dispatcher: @NonBlockingExecutor CoroutineContext
          get() { ... }

      suspend fun foo() {
          val result = withContext(dispatcher) {
              blockingBuzz() // IDE warning: `Possibly blocking call in non-blocking context`
          }
      }

      @Blocking fun blockingBuzz() { ... }
  }
 

Example 2 (Java with Reactor framework):

  class NonBlockingExampleService {
      private static final @NonBlockingExecutor Scheduler operationsScheduler =
              Schedulers.newParallel("parallel");

      public Flux<String> foo(Flux<String> urls) {
          return urls.publishOn(operationsScheduler)
                  .filter(url -> blockingBuzz(url) != null);  // IDE warning: `Possibly blocking call in non-blocking context`
      }

      @Blocking
      private String blockingBuzz(String url) { ... }
  }
 

See Also:

Blocking, NonBlocking