Package org.jetbrains.annotations

# Annotation Interface 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`