@SuppressWarnings("unchecked")
@Test
public void mustBeAbleToUseGroupBy() throws Exception {
final Iterable<String> input = Arrays.asList("Aaa", "Abb", "Bcc", "Cdd", "Cee");
final Source<List<String>, NotUsed> source =
Source.from(input)
.groupBy(
3,
new Function<String, String>() {
public String apply(String elem) {
return elem.substring(0, 1);
}
})
.grouped(10)
.mergeSubstreams();
final CompletionStage<List<List<String>>> future =
source.grouped(10).runWith(Sink.<List<List<String>>>head(), materializer);
final Object[] result = future.toCompletableFuture().get(1, TimeUnit.SECONDS).toArray();
Arrays.sort(
result,
(Comparator<Object>)
(Object)
new Comparator<List<String>>() {
@Override
public int compare(List<String> o1, List<String> o2) {
return o1.get(0).charAt(0) - o2.get(0).charAt(0);
}
});
assertArrayEquals(
new Object[] {
Arrays.asList("Aaa", "Abb"), Arrays.asList("Bcc"), Arrays.asList("Cdd", "Cee")
},
result);
}
