Merge pull request #14415 from etrandafir93/features/BAEL-6578-CompletableFuture_allOf_vs_join

BAEL-6578: CompletableFuture allOf.join() vs join()
This commit is contained in:
davidmartinezbarua 2023-07-22 10:19:55 -03:00 committed by GitHub
commit 9b90e43d85
1 changed files with 112 additions and 0 deletions

View File

@ -0,0 +1,112 @@
package com.baeldung.concurrent.completablefuture.allofvsjoin;
import static org.junit.Assert.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import java.time.LocalDateTime;
import java.util.concurrent.CompletableFuture;
import java.util.stream.Stream;
import org.junit.jupiter.api.Test;
public class CompletableFutureAllOffUnitTest {
@Test
void whenCallingJoin_thenBlocksThreadAndGetValue() {
CompletableFuture<String> future = waitAndReturn(1_000, "Harry");
assertEquals("Harry", future.join());
}
@Test
void whenCallingJoin_thenBlocksThreadAndThrowException() {
CompletableFuture<String> futureError = waitAndThrow(1_000);
assertThrows(RuntimeException.class, futureError::join);
}
@Test
void whenCallingJoinTwoTimes_thenBlocksThreadAndGetValues() {
CompletableFuture<String> f1 = waitAndReturn(1_000, "Harry");
CompletableFuture<String> f2 = waitAndReturn(2_000, "Ron");
assertEquals("Harry", f1.join());
assertEquals("Ron", f2.join());
}
@Test
void whenCallingAllOfJoin_thenBlocksThreadAndGetValues() {
CompletableFuture<String> f1 = waitAndReturn(1_000, "Harry");
CompletableFuture<String> f2 = waitAndReturn(2_000, "Ron");
CompletableFuture<Void> combinedFutures = CompletableFuture.allOf(f1, f2);
combinedFutures.join();
assertEquals("Harry", f1.join());
assertEquals("Ron", f2.join());
}
@Test
void whenCallingJoinInaLoop_thenProcessesDataPartially() {
CompletableFuture<String> f1 = waitAndReturn(1_000, "Harry");
CompletableFuture<String> f2 = waitAndThrow(2_000);
CompletableFuture<String> f3 = waitAndReturn(1_000, "Ron");
assertThrows(RuntimeException.class, () -> Stream.of(f1, f2, f3)
.map(CompletableFuture::join)
.forEach(this::sayHello));
}
@Test
void whenCallingAllOfJoin_thenFailsForAll() {
CompletableFuture<String> f1 = waitAndReturn(1_000, "Harry");
CompletableFuture<String> f2 = waitAndThrow(2_000);
CompletableFuture<String> f3 = waitAndReturn(1_000, "Ron");
assertThrows(RuntimeException.class, () -> CompletableFuture.allOf(f1, f2, f3)
.join());
}
@Test
void whenCallingExceptionally_thenRecoversWithDefaultValue() {
CompletableFuture<String> f1 = waitAndReturn(1_000, "Harry");
CompletableFuture<String> f2 = waitAndThrow(2_000);
CompletableFuture<String> f3 = waitAndReturn(1_000, "Ron");
CompletableFuture<String> names = CompletableFuture.allOf(f1, f2, f3)
.thenApply(__ -> f1.join() + "," + f2.join() + "," + f3.join())
.exceptionally(err -> {
System.out.println("oops, there was a problem! " + err.getMessage());
return "names not found!";
});
assertEquals("names not found!", names.join());
}
private void sayHello(String name) {
System.out.println(LocalDateTime.now() + " - " + name);
}
private CompletableFuture<String> waitAndReturn(long millis, String value) {
return CompletableFuture.supplyAsync(() -> {
try {
// Thread.sleep() is commented to avoid slowing down the pipeline
// Thread.sleep(millis);
return value;
} catch (Exception e) {
throw new RuntimeException(e);
}
});
}
private CompletableFuture<String> waitAndThrow(long millis) {
return CompletableFuture.supplyAsync(() -> {
try {
// Thread.sleep() is commented to avoid slowing down the pipeline
// Thread.sleep(millis);
} finally {
throw new RuntimeException();
}
});
}
}