那就是这样了。实在找不到任何相似的东西。我想要实现以下任务链。
List<Item> items = Collections.singletonList(new Item("John Smith", "1997-2014"));
Stream<CompletableFuture<List<ScrappingResult>>> scrappingFutures =
items.stream().map(item ->
CompletableFuture.supplyAsync(() -> new ScrappingTask(item).call()));
Stream<CompletableFuture<ScrappingResult>> scrappingFuturesUnwrapped =
scrappingFutures.map(resultsFuture -> ???);
Stream<CompletableFuture<TrimmingResult>> trimmingResults = scrappingFuturesUnwrapped.map(resultFuture ->
// thenCompose?
resultFuture.thenCompose(result -> {
Path clipsDir = Paths.get("./"
+ result.getItem().getName()
+ "/" + result.getItem().getTimespan());
AtomicInteger clipIdx = new AtomicInteger();
return result.getVideo().getClips().stream()
.map(clip -> CompletableFuture.supplyAsync(() ->
new TrimmingTask(
ffmpegPath,
result.getVideo().getVideoUrl(),
clip,
clipsDir.resolve("clip_" + clipIdx.incrementAndGet() + ".mp3")).call())
);
});
);
最后一行语法不正确,但我希望能传达这个想法。所以,我想执行类似于flatMap两次,最终得到Stream<CompletableFuture<TrimmingResult>>
。
我该怎么做呢?
谢谢。
CompletableFuture<Stream<T>>
. - Holger