／var／logmarcus chiu

Java - CompletableFuture

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CompletableFuture
  • is an implementation of Future

Creating CompletableFutures

CompletableFuture<String> completableFuture = CompletableFuture.completedFuture("Hello");
assertEquals("Hello", completableFuture.get());

CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello");
assertEquals("Hello", completableFuture.get());

Processing Results of Asynchronous Computations

CompletableFuture<String> future = completableFuture.thenApply(s -> s + " World");

CompletableFuture<Void> future = completableFuture.thenAccept(s -> System.out.println("Computation returned: " + s));

CompletableFuture<Void> future = completableFuture.thenRun(() -> System.out.println("Computation finished."));

Combining Futures

TODO

Multiple Parallel Futures

CompletableFuture<String> future1 = CompletableFuture.supplyAsync(() -> "Hello");
CompletableFuture<String> future2 = CompletableFuture.supplyAsync(() -> "Beautiful");
CompletableFuture<String> future3 = CompletableFuture.supplyAsync(() -> "World");

CompletableFuture<Void> combinedFuture = CompletableFuture.allOf(future1, future2, future3);

combinedFuture.get();

assertTrue(future1.isDone());
assertTrue(future2.isDone());
assertTrue(future3.isDone());

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