--- jsr166/src/test/tck/CompletableFutureTest.java 2015/10/25 02:58:25 1.127 +++ jsr166/src/test/tck/CompletableFutureTest.java 2016/04/03 17:09:46 1.143 @@ -7,6 +7,8 @@ import static java.util.concurrent.TimeUnit.MILLISECONDS; import static java.util.concurrent.TimeUnit.SECONDS; +import static java.util.concurrent.CompletableFuture.completedFuture; +import static java.util.concurrent.CompletableFuture.failedFuture; import java.lang.reflect.Method; import java.lang.reflect.Modifier; @@ -39,6 +41,7 @@ import java.util.function.Function; import java.util.function.Predicate; import java.util.function.Supplier; +import junit.framework.AssertionFailedError; import junit.framework.Test; import junit.framework.TestSuite; @@ -637,8 +640,12 @@ public class CompletableFutureTest exten ASYNC { public void checkExecutionMode() { - assertEquals(defaultExecutorIsCommonPool, - (ForkJoinPool.commonPool() == ForkJoinTask.getPool())); + // If tests are added that may run across different + // pools, this needs to be weakened to no-op. + ForkJoinPool p = ForkJoinTask.getPool(); + assertTrue(p == null || + (defaultExecutorIsCommonPool && + p == ForkJoinPool.commonPool())); } public CompletableFuture runAsync(Runnable a) { return CompletableFuture.runAsync(a); @@ -873,6 +880,10 @@ public class CompletableFutureTest exten assertEquals(1, a.get()); }} + /** + * If an "exceptionally action" throws an exception, it completes + * exceptionally with that exception + */ public void testExceptionally_exceptionalCompletionActionFailed() { for (boolean createIncomplete : new boolean[] { true, false }) { @@ -891,6 +902,7 @@ public class CompletableFutureTest exten if (createIncomplete) f.completeExceptionally(ex1); checkCompletedWithWrappedException(g, ex2); + checkCompletedExceptionally(f, ex1); assertEquals(1, a.get()); }} @@ -908,9 +920,9 @@ public class CompletableFutureTest exten if (!createIncomplete) assertTrue(f.complete(v1)); final CompletableFuture g = m.whenComplete (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertSame(x, v1); + threadAssertSame(result, v1); threadAssertNull(t); a.getAndIncrement(); }); @@ -935,9 +947,9 @@ public class CompletableFutureTest exten if (!createIncomplete) f.completeExceptionally(ex); final CompletableFuture g = m.whenComplete (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertNull(x); + threadAssertNull(result); threadAssertSame(t, ex); a.getAndIncrement(); }); @@ -962,9 +974,9 @@ public class CompletableFutureTest exten if (!createIncomplete) assertTrue(f.cancel(mayInterruptIfRunning)); final CompletableFuture g = m.whenComplete (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertNull(x); + threadAssertNull(result); threadAssertTrue(t instanceof CancellationException); a.getAndIncrement(); }); @@ -979,7 +991,7 @@ public class CompletableFutureTest exten * If a whenComplete action throws an exception when triggered by * a normal completion, it completes exceptionally */ - public void testWhenComplete_actionFailed() { + public void testWhenComplete_sourceCompletedNormallyActionFailed() { for (boolean createIncomplete : new boolean[] { true, false }) for (ExecutionMode m : ExecutionMode.values()) for (Integer v1 : new Integer[] { 1, null }) @@ -990,9 +1002,9 @@ public class CompletableFutureTest exten if (!createIncomplete) assertTrue(f.complete(v1)); final CompletableFuture g = m.whenComplete (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertSame(x, v1); + threadAssertSame(result, v1); threadAssertNull(t); a.getAndIncrement(); throw ex; @@ -1007,9 +1019,9 @@ public class CompletableFutureTest exten /** * If a whenComplete action throws an exception when triggered by * a source completion that also throws an exception, the source - * exception takes precedence. + * exception takes precedence (unlike handle) */ - public void testWhenComplete_actionFailedSourceFailed() { + public void testWhenComplete_sourceFailedActionFailed() { for (boolean createIncomplete : new boolean[] { true, false }) for (ExecutionMode m : ExecutionMode.values()) { @@ -1021,10 +1033,10 @@ public class CompletableFutureTest exten if (!createIncomplete) f.completeExceptionally(ex1); final CompletableFuture g = m.whenComplete (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); threadAssertSame(t, ex1); - threadAssertNull(x); + threadAssertNull(result); a.getAndIncrement(); throw ex2; }); @@ -1032,6 +1044,10 @@ public class CompletableFutureTest exten checkCompletedWithWrappedException(g, ex1); checkCompletedExceptionally(f, ex1); + if (testImplementationDetails) { + assertEquals(1, ex1.getSuppressed().length); + assertSame(ex2, ex1.getSuppressed()[0]); + } assertEquals(1, a.get()); }} @@ -1049,9 +1065,9 @@ public class CompletableFutureTest exten if (!createIncomplete) assertTrue(f.complete(v1)); final CompletableFuture g = m.handle (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertSame(x, v1); + threadAssertSame(result, v1); threadAssertNull(t); a.getAndIncrement(); return inc(v1); @@ -1078,9 +1094,9 @@ public class CompletableFutureTest exten if (!createIncomplete) f.completeExceptionally(ex); final CompletableFuture g = m.handle (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertNull(x); + threadAssertNull(result); threadAssertSame(t, ex); a.getAndIncrement(); return v1; @@ -1107,9 +1123,9 @@ public class CompletableFutureTest exten if (!createIncomplete) assertTrue(f.cancel(mayInterruptIfRunning)); final CompletableFuture g = m.handle (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertNull(x); + threadAssertNull(result); threadAssertTrue(t instanceof CancellationException); a.getAndIncrement(); return v1; @@ -1122,55 +1138,62 @@ public class CompletableFutureTest exten }} /** - * handle result completes exceptionally if action does + * If a "handle action" throws an exception when triggered by + * a normal completion, it completes exceptionally */ - public void testHandle_sourceFailedActionFailed() { + public void testHandle_sourceCompletedNormallyActionFailed() { for (ExecutionMode m : ExecutionMode.values()) for (boolean createIncomplete : new boolean[] { true, false }) + for (Integer v1 : new Integer[] { 1, null }) { final CompletableFuture f = new CompletableFuture<>(); final AtomicInteger a = new AtomicInteger(0); - final CFException ex1 = new CFException(); - final CFException ex2 = new CFException(); - if (!createIncomplete) f.completeExceptionally(ex1); + final CFException ex = new CFException(); + if (!createIncomplete) assertTrue(f.complete(v1)); final CompletableFuture g = m.handle (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertNull(x); - threadAssertSame(ex1, t); + threadAssertSame(result, v1); + threadAssertNull(t); a.getAndIncrement(); - throw ex2; + throw ex; }); - if (createIncomplete) f.completeExceptionally(ex1); + if (createIncomplete) assertTrue(f.complete(v1)); - checkCompletedWithWrappedException(g, ex2); - checkCompletedExceptionally(f, ex1); + checkCompletedWithWrappedException(g, ex); + checkCompletedNormally(f, v1); assertEquals(1, a.get()); }} - public void testHandle_sourceCompletedNormallyActionFailed() { - for (ExecutionMode m : ExecutionMode.values()) + /** + * If a "handle action" throws an exception when triggered by + * a source completion that also throws an exception, the action + * exception takes precedence (unlike whenComplete) + */ + public void testHandle_sourceFailedActionFailed() { for (boolean createIncomplete : new boolean[] { true, false }) - for (Integer v1 : new Integer[] { 1, null }) + for (ExecutionMode m : ExecutionMode.values()) { - final CompletableFuture f = new CompletableFuture<>(); final AtomicInteger a = new AtomicInteger(0); - final CFException ex = new CFException(); - if (!createIncomplete) assertTrue(f.complete(v1)); + final CFException ex1 = new CFException(); + final CFException ex2 = new CFException(); + final CompletableFuture f = new CompletableFuture<>(); + + if (!createIncomplete) f.completeExceptionally(ex1); final CompletableFuture g = m.handle (f, - (Integer x, Throwable t) -> { + (Integer result, Throwable t) -> { m.checkExecutionMode(); - threadAssertSame(x, v1); - threadAssertNull(t); + threadAssertNull(result); + threadAssertSame(ex1, t); a.getAndIncrement(); - throw ex; + throw ex2; }); - if (createIncomplete) assertTrue(f.complete(v1)); + if (createIncomplete) f.completeExceptionally(ex1); - checkCompletedWithWrappedException(g, ex); - checkCompletedNormally(f, v1); + checkCompletedWithWrappedException(g, ex2); + checkCompletedExceptionally(f, ex1); assertEquals(1, a.get()); }} @@ -3276,7 +3299,7 @@ public class CompletableFutureTest exten () -> f.obtrudeException(null), () -> CompletableFuture.delayedExecutor(1L, SECONDS, null), - () -> CompletableFuture.delayedExecutor(1L, null, new ThreadExecutor()), + () -> CompletableFuture.delayedExecutor(1L, null, exec), () -> CompletableFuture.delayedExecutor(1L, null), () -> f.orTimeout(1L, null), @@ -3641,7 +3664,7 @@ public class CompletableFutureTest exten funs.add((y) -> m.thenAcceptBoth(y, v42, new SubtractAction(m))); funs.add((y) -> m.thenCombine(y, v42, new SubtractFunction(m))); - funs.add((y) -> m.whenComplete(y, (Integer x, Throwable t) -> {})); + funs.add((y) -> m.whenComplete(y, (Integer r, Throwable t) -> {})); funs.add((y) -> m.thenCompose(y, new CompletableFutureInc(m))); @@ -3760,6 +3783,184 @@ public class CompletableFutureTest exten throw new Error("Methods did not throw UOE: " + bugs.toString()); } + static class Monad { + static class ZeroException extends RuntimeException { + public ZeroException() { super("monadic zero"); } + } + // "return", "unit" + static CompletableFuture unit(T value) { + return completedFuture(value); + } + // monadic zero ? + static CompletableFuture zero() { + return failedFuture(new ZeroException()); + } + // >=> + static Function> compose + (Function> f, + Function> g) { + return (x) -> f.apply(x).thenCompose(g); + } + + static void assertZero(CompletableFuture f) { + try { + f.getNow(null); + throw new AssertionFailedError("should throw"); + } catch (CompletionException success) { + assertTrue(success.getCause() instanceof ZeroException); + } + } + + static void assertFutureEquals(CompletableFuture f, + CompletableFuture g) { + T fval = null, gval = null; + Throwable fex = null, gex = null; + + try { fval = f.get(); } + catch (ExecutionException ex) { fex = ex.getCause(); } + catch (Throwable ex) { fex = ex; } + + try { gval = g.get(); } + catch (ExecutionException ex) { gex = ex.getCause(); } + catch (Throwable ex) { gex = ex; } + + if (fex != null || gex != null) + assertSame(fex.getClass(), gex.getClass()); + else + assertEquals(fval, gval); + } + + static class PlusFuture extends CompletableFuture { + AtomicReference firstFailure = new AtomicReference<>(null); + } + + /** Implements "monadic plus". */ + static CompletableFuture plus(CompletableFuture f, + CompletableFuture g) { + PlusFuture plus = new PlusFuture(); + BiConsumer action = (T result, Throwable ex) -> { + try { + if (ex == null) { + if (plus.complete(result)) + if (plus.firstFailure.get() != null) + plus.firstFailure.set(null); + } + else if (plus.firstFailure.compareAndSet(null, ex)) { + if (plus.isDone()) + plus.firstFailure.set(null); + } + else { + // first failure has precedence + Throwable first = plus.firstFailure.getAndSet(null); + + // may fail with "Self-suppression not permitted" + try { first.addSuppressed(ex); } + catch (Exception ignored) {} + + plus.completeExceptionally(first); + } + } catch (Throwable unexpected) { + plus.completeExceptionally(unexpected); + } + }; + f.whenComplete(action); + g.whenComplete(action); + return plus; + } + } + + /** + * CompletableFuture is an additive monad - sort of. + * https://en.wikipedia.org/wiki/Monad_(functional_programming)#Additive_monads + */ + public void testAdditiveMonad() throws Throwable { + Function> unit = Monad::unit; + CompletableFuture zero = Monad.zero(); + + // Some mutually non-commutative functions + Function> triple + = (x) -> Monad.unit(3 * x); + Function> inc + = (x) -> Monad.unit(x + 1); + + // unit is a right identity: m >>= unit === m + Monad.assertFutureEquals(inc.apply(5L).thenCompose(unit), + inc.apply(5L)); + // unit is a left identity: (unit x) >>= f === f x + Monad.assertFutureEquals(unit.apply(5L).thenCompose(inc), + inc.apply(5L)); + + // associativity: (m >>= f) >>= g === m >>= ( \x -> (f x >>= g) ) + Monad.assertFutureEquals( + unit.apply(5L).thenCompose(inc).thenCompose(triple), + unit.apply(5L).thenCompose((x) -> inc.apply(x).thenCompose(triple))); + + // The case for CompletableFuture as an additive monad is weaker... + + // zero is a monadic zero + Monad.assertZero(zero); + + // left zero: zero >>= f === zero + Monad.assertZero(zero.thenCompose(inc)); + // right zero: f >>= (\x -> zero) === zero + Monad.assertZero(inc.apply(5L).thenCompose((x) -> zero)); + + // f plus zero === f + Monad.assertFutureEquals(Monad.unit(5L), + Monad.plus(Monad.unit(5L), zero)); + // zero plus f === f + Monad.assertFutureEquals(Monad.unit(5L), + Monad.plus(zero, Monad.unit(5L))); + // zero plus zero === zero + Monad.assertZero(Monad.plus(zero, zero)); + { + CompletableFuture f = Monad.plus(Monad.unit(5L), + Monad.unit(8L)); + // non-determinism + assertTrue(f.get() == 5L || f.get() == 8L); + } + + CompletableFuture godot = new CompletableFuture<>(); + // f plus godot === f (doesn't wait for godot) + Monad.assertFutureEquals(Monad.unit(5L), + Monad.plus(Monad.unit(5L), godot)); + // godot plus f === f (doesn't wait for godot) + Monad.assertFutureEquals(Monad.unit(5L), + Monad.plus(godot, Monad.unit(5L))); + } + + /** + * A single CompletableFuture with many dependents. + * A demo of scalability - runtime is O(n). + */ + public void testManyDependents() throws Throwable { + final int n = 1_000; + final CompletableFuture head = new CompletableFuture<>(); + final CompletableFuture complete = CompletableFuture.completedFuture((Void)null); + final AtomicInteger count = new AtomicInteger(0); + for (int i = 0; i < n; i++) { + head.thenRun(() -> count.getAndIncrement()); + head.thenAccept((x) -> count.getAndIncrement()); + head.thenApply((x) -> count.getAndIncrement()); + + head.runAfterBoth(complete, () -> count.getAndIncrement()); + head.thenAcceptBoth(complete, (x, y) -> count.getAndIncrement()); + head.thenCombine(complete, (x, y) -> count.getAndIncrement()); + complete.runAfterBoth(head, () -> count.getAndIncrement()); + complete.thenAcceptBoth(head, (x, y) -> count.getAndIncrement()); + complete.thenCombine(head, (x, y) -> count.getAndIncrement()); + + head.runAfterEither(new CompletableFuture(), () -> count.getAndIncrement()); + head.acceptEither(new CompletableFuture(), (x) -> count.getAndIncrement()); + head.applyToEither(new CompletableFuture(), (x) -> count.getAndIncrement()); + new CompletableFuture().runAfterEither(head, () -> count.getAndIncrement()); + new CompletableFuture().acceptEither(head, (x) -> count.getAndIncrement()); + new CompletableFuture().applyToEither(head, (x) -> count.getAndIncrement()); + } + head.complete(null); + assertEquals(5 * 3 * n, count.get()); + } + // static U join(CompletionStage stage) { // CompletableFuture f = new CompletableFuture<>(); // stage.whenComplete((v, ex) -> {