@Test
public void mustWorkFromFuture() throws Exception {
final Iterable<String> input = Arrays.asList("A", "B", "C");
CompletionStage<String> future1 = Source.from(input).runWith(Sink.<String>head(), materializer);
CompletionStage<String> future2 =
Source.fromCompletionStage(future1).runWith(Sink.<String>head(), materializer);
String result = future2.toCompletableFuture().get(3, TimeUnit.SECONDS);
assertEquals("A", result);
}
@Test
public void demonstrateAnAsynchronousSideChannel() throws Exception {
// tests:
CompletableFuture<Done> switchF = new CompletableFuture<>();
Graph<FlowShape<Integer, Integer>, NotUsed> killSwitch =
Flow.fromGraph(new KillSwitch<>(switchF));
ExecutionContext ec = system.dispatcher();
CompletionStage<Integer> valueAfterKill = switchF.thenApply(in -> 4);
CompletionStage<Integer> result =
Source.from(Arrays.asList(1, 2, 3))
.concat(Source.fromCompletionStage(valueAfterKill))
.via(killSwitch)
.runFold(0, (n, sum) -> n + sum, mat);
switchF.complete(Done.getInstance());
assertEquals(new Integer(6), result.toCompletableFuture().get(3, TimeUnit.SECONDS));
}