public Stream<CompletableFuture<String>> findPriceStream(String product) {
return shops
.stream()
.map(shop -> CompletableFuture.supplyAsync(() -> shop.getPrice(product), executor))
.map(future -> future.thenApply(Quote::parse))
.map(
future ->
future.thenCompose(
quote ->
CompletableFuture.supplyAsync(
() -> Discount.applyDiscount(quote), executor)));
}
public void printPricesStream() {
long start = System.nanoTime();
CompletableFuture[] futures =
findPriceStream("myPhone")
.map(
f ->
f.thenAccept(
s ->
System.out.println(
s
+ " (done in "
+ ((System.nanoTime() - start) / 1_000_000)
+ " msecs)")))
.toArray(size -> new CompletableFuture[size]);
CompletableFuture.allOf(futures).join();
}