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Comparing jsr166/src/test/tck/CompletableFutureTest.java (file contents):
Revision 1.95 by jsr166, Wed Jun 25 15:32:10 2014 UTC vs.
Revision 1.139 by jsr166, Sat Jan 23 20:02:48 2016 UTC

#	Line 5 | Line 5
5		* http://creativecommons.org/publicdomain/zero/1.0/
6		*/
7
8	<	import junit.framework.*;
8	>	import static java.util.concurrent.TimeUnit.MILLISECONDS;
9	>	import static java.util.concurrent.TimeUnit.SECONDS;
10	>	import static java.util.concurrent.CompletableFuture.completedFuture;
11	>	import static java.util.concurrent.CompletableFuture.failedFuture;
12	>
13	>	import java.lang.reflect.Method;
14	>	import java.lang.reflect.Modifier;
15	>
16	>	import java.util.stream.Collectors;
17	>	import java.util.stream.Stream;
18	>
19	>	import java.util.ArrayList;
20	>	import java.util.Arrays;
21	>	import java.util.List;
22	>	import java.util.Objects;
23	>	import java.util.Set;
24		import java.util.concurrent.Callable;
10	–	import java.util.concurrent.Executor;
11	–	import java.util.concurrent.ExecutorService;
12	–	import java.util.concurrent.Executors;
25		import java.util.concurrent.CancellationException;
14	–	import java.util.concurrent.CountDownLatch;
15	–	import java.util.concurrent.ExecutionException;
16	–	import java.util.concurrent.Future;
26		import java.util.concurrent.CompletableFuture;
27		import java.util.concurrent.CompletionException;
28		import java.util.concurrent.CompletionStage;
29	+	import java.util.concurrent.ExecutionException;
30	+	import java.util.concurrent.Executor;
31		import java.util.concurrent.ForkJoinPool;
32		import java.util.concurrent.ForkJoinTask;
33		import java.util.concurrent.TimeoutException;
34	+	import java.util.concurrent.TimeUnit;
35		import java.util.concurrent.atomic.AtomicInteger;
36	<	import static java.util.concurrent.TimeUnit.MILLISECONDS;
25	<	import static java.util.concurrent.TimeUnit.SECONDS;
26	<	import java.util.*;
27	<	import java.util.function.Supplier;
28	<	import java.util.function.Consumer;
36	>	import java.util.concurrent.atomic.AtomicReference;
37		import java.util.function.BiConsumer;
30	–	import java.util.function.Function;
38		import java.util.function.BiFunction;
39	+	import java.util.function.Consumer;
40	+	import java.util.function.Function;
41	+	import java.util.function.Predicate;
42	+	import java.util.function.Supplier;
43	+
44	+	import junit.framework.AssertionFailedError;
45	+	import junit.framework.Test;
46	+	import junit.framework.TestSuite;
47
48		public class CompletableFutureTest extends JSR166TestCase {
49
50		public static void main(String[] args) {
51	<	junit.textui.TestRunner.run(suite());
51	>	main(suite(), args);
52		}
53		public static Test suite() {
54		return new TestSuite(CompletableFutureTest.class);
#	Line 44 | Line 59 | public class CompletableFutureTest exten
59		void checkIncomplete(CompletableFuture<?> f) {
60		assertFalse(f.isDone());
61		assertFalse(f.isCancelled());
62	<	assertTrue(f.toString().contains("[Not completed]"));
62	>	assertTrue(f.toString().contains("Not completed"));
63		try {
64		assertNull(f.getNow(null));
65		} catch (Throwable fail) { threadUnexpectedException(fail); }
#	Line 74 | Line 89 | public class CompletableFutureTest exten
89		assertTrue(f.toString().contains("[Completed normally]"));
90		}
91
92	<	void checkCompletedWithWrappedCFException(CompletableFuture<?> f) {
92	>	/**
93	>	* Returns the "raw" internal exceptional completion of f,
94	>	* without any additional wrapping with CompletionException.
95	>	*/
96	>	<U> Throwable exceptionalCompletion(CompletableFuture<U> f) {
97	>	// handle (and whenComplete) can distinguish between "direct"
98	>	// and "wrapped" exceptional completion
99	>	return f.handle((U u, Throwable t) -> t).join();
100	>	}
101	>
102	>	void checkCompletedExceptionally(CompletableFuture<?> f,
103	>	boolean wrapped,
104	>	Consumer<Throwable> checker) {
105	>	Throwable cause = exceptionalCompletion(f);
106	>	if (wrapped) {
107	>	assertTrue(cause instanceof CompletionException);
108	>	cause = cause.getCause();
109	>	}
110	>	checker.accept(cause);
111	>
112		long startTime = System.nanoTime();
79	–	long timeoutMillis = LONG_DELAY_MS;
113		try {
114	<	f.get(timeoutMillis, MILLISECONDS);
114	>	f.get(LONG_DELAY_MS, MILLISECONDS);
115		shouldThrow();
116		} catch (ExecutionException success) {
117	<	assertTrue(success.getCause() instanceof CFException);
117	>	assertSame(cause, success.getCause());
118		} catch (Throwable fail) { threadUnexpectedException(fail); }
119	<	assertTrue(millisElapsedSince(startTime) < timeoutMillis/2);
119	>	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS / 2);
120
121		try {
122		f.join();
123		shouldThrow();
124		} catch (CompletionException success) {
125	<	assertTrue(success.getCause() instanceof CFException);
126	<	}
125	>	assertSame(cause, success.getCause());
126	>	} catch (Throwable fail) { threadUnexpectedException(fail); }
127	>
128		try {
129		f.getNow(null);
130		shouldThrow();
131		} catch (CompletionException success) {
132	<	assertTrue(success.getCause() instanceof CFException);
133	<	}
132	>	assertSame(cause, success.getCause());
133	>	} catch (Throwable fail) { threadUnexpectedException(fail); }
134	>
135		try {
136		f.get();
137		shouldThrow();
138		} catch (ExecutionException success) {
139	<	assertTrue(success.getCause() instanceof CFException);
139	>	assertSame(cause, success.getCause());
140		} catch (Throwable fail) { threadUnexpectedException(fail); }
141	<	assertTrue(f.isDone());
141	>
142		assertFalse(f.isCancelled());
143	+	assertTrue(f.isDone());
144	+	assertTrue(f.isCompletedExceptionally());
145		assertTrue(f.toString().contains("[Completed exceptionally]"));
146		}
147
148	<	<U> void checkCompletedExceptionallyWithRootCause(CompletableFuture<U> f,
149	<	Throwable ex) {
150	<	long startTime = System.nanoTime();
151	<	long timeoutMillis = LONG_DELAY_MS;
115	<	try {
116	<	f.get(timeoutMillis, MILLISECONDS);
117	<	shouldThrow();
118	<	} catch (ExecutionException success) {
119	<	assertSame(ex, success.getCause());
120	<	} catch (Throwable fail) { threadUnexpectedException(fail); }
121	<	assertTrue(millisElapsedSince(startTime) < timeoutMillis/2);
148	>	void checkCompletedWithWrappedCFException(CompletableFuture<?> f) {
149	>	checkCompletedExceptionally(f, true,
150	>	(t) -> assertTrue(t instanceof CFException));
151	>	}
152
153	<	try {
154	<	f.join();
155	<	shouldThrow();
156	<	} catch (CompletionException success) {
127	<	assertSame(ex, success.getCause());
128	<	}
129	<	try {
130	<	f.getNow(null);
131	<	shouldThrow();
132	<	} catch (CompletionException success) {
133	<	assertSame(ex, success.getCause());
134	<	}
135	<	try {
136	<	f.get();
137	<	shouldThrow();
138	<	} catch (ExecutionException success) {
139	<	assertSame(ex, success.getCause());
140	<	} catch (Throwable fail) { threadUnexpectedException(fail); }
153	>	void checkCompletedWithWrappedCancellationException(CompletableFuture<?> f) {
154	>	checkCompletedExceptionally(f, true,
155	>	(t) -> assertTrue(t instanceof CancellationException));
156	>	}
157
158	<	assertTrue(f.isDone());
159	<	assertFalse(f.isCancelled());
160	<	assertTrue(f.toString().contains("[Completed exceptionally]"));
158	>	void checkCompletedWithTimeoutException(CompletableFuture<?> f) {
159	>	checkCompletedExceptionally(f, false,
160	>	(t) -> assertTrue(t instanceof TimeoutException));
161		}
162
163	<	<U> void checkCompletedWithWrappedException(CompletableFuture<U> f,
164	<	Throwable ex) {
165	<	checkCompletedExceptionallyWithRootCause(f, ex);
150	<	try {
151	<	CompletableFuture<Throwable> spy = f.handle
152	<	((U u, Throwable t) -> t);
153	<	assertTrue(spy.join() instanceof CompletionException);
154	<	assertSame(ex, spy.join().getCause());
155	<	} catch (Throwable fail) { threadUnexpectedException(fail); }
163	>	void checkCompletedWithWrappedException(CompletableFuture<?> f,
164	>	Throwable ex) {
165	>	checkCompletedExceptionally(f, true, (t) -> assertSame(t, ex));
166		}
167
168	<	<U> void checkCompletedExceptionally(CompletableFuture<U> f, Throwable ex) {
169	<	checkCompletedExceptionallyWithRootCause(f, ex);
160	<	try {
161	<	CompletableFuture<Throwable> spy = f.handle
162	<	((U u, Throwable t) -> t);
163	<	assertSame(ex, spy.join());
164	<	} catch (Throwable fail) { threadUnexpectedException(fail); }
168	>	void checkCompletedExceptionally(CompletableFuture<?> f, Throwable ex) {
169	>	checkCompletedExceptionally(f, false, (t) -> assertSame(t, ex));
170		}
171
172		void checkCancelled(CompletableFuture<?> f) {
173		long startTime = System.nanoTime();
169	–	long timeoutMillis = LONG_DELAY_MS;
174		try {
175	<	f.get(timeoutMillis, MILLISECONDS);
175	>	f.get(LONG_DELAY_MS, MILLISECONDS);
176		shouldThrow();
177		} catch (CancellationException success) {
178		} catch (Throwable fail) { threadUnexpectedException(fail); }
179	<	assertTrue(millisElapsedSince(startTime) < timeoutMillis/2);
179	>	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS / 2);
180
181		try {
182		f.join();
#	Line 187 | Line 191 | public class CompletableFutureTest exten
191		shouldThrow();
192		} catch (CancellationException success) {
193		} catch (Throwable fail) { threadUnexpectedException(fail); }
190	–	assertTrue(f.isDone());
191	–	assertTrue(f.isCompletedExceptionally());
192	–	assertTrue(f.isCancelled());
193	–	assertTrue(f.toString().contains("[Completed exceptionally]"));
194	–	}
194
195	<	void checkCompletedWithWrappedCancellationException(CompletableFuture<?> f) {
197	<	long startTime = System.nanoTime();
198	<	long timeoutMillis = LONG_DELAY_MS;
199	<	try {
200	<	f.get(timeoutMillis, MILLISECONDS);
201	<	shouldThrow();
202	<	} catch (ExecutionException success) {
203	<	assertTrue(success.getCause() instanceof CancellationException);
204	<	} catch (Throwable fail) { threadUnexpectedException(fail); }
205	<	assertTrue(millisElapsedSince(startTime) < timeoutMillis/2);
195	>	assertTrue(exceptionalCompletion(f) instanceof CancellationException);
196
207	–	try {
208	–	f.join();
209	–	shouldThrow();
210	–	} catch (CompletionException success) {
211	–	assertTrue(success.getCause() instanceof CancellationException);
212	–	}
213	–	try {
214	–	f.getNow(null);
215	–	shouldThrow();
216	–	} catch (CompletionException success) {
217	–	assertTrue(success.getCause() instanceof CancellationException);
218	–	}
219	–	try {
220	–	f.get();
221	–	shouldThrow();
222	–	} catch (ExecutionException success) {
223	–	assertTrue(success.getCause() instanceof CancellationException);
224	–	} catch (Throwable fail) { threadUnexpectedException(fail); }
197		assertTrue(f.isDone());
226	–	assertFalse(f.isCancelled());
198		assertTrue(f.isCompletedExceptionally());
199	+	assertTrue(f.isCancelled());
200		assertTrue(f.toString().contains("[Completed exceptionally]"));
201		}
202
#	Line 272 | Line 244 | public class CompletableFutureTest exten
244		{
245		CompletableFuture<Integer> f = new CompletableFuture<>();
246		checkIncomplete(f);
247	<	assertTrue(f.cancel(true));
248	<	assertTrue(f.cancel(true));
247	>	assertTrue(f.cancel(mayInterruptIfRunning));
248	>	assertTrue(f.cancel(mayInterruptIfRunning));
249	>	assertTrue(f.cancel(!mayInterruptIfRunning));
250		checkCancelled(f);
251		}}
252
#	Line 545 | Line 518 | public class CompletableFutureTest exten
518		}
519		}
520
548	–
521		class CompletableFutureInc extends CheckedIntegerAction
522		implements Function<Integer, CompletableFuture<Integer>>
523		{
#	Line 584 | Line 556 | public class CompletableFutureTest exten
556		}
557		}
558
559	+	static final boolean defaultExecutorIsCommonPool
560	+	= ForkJoinPool.getCommonPoolParallelism() > 1;
561	+
562		/**
563		* Permits the testing of parallel code for the 3 different
564		* execution modes without copy/pasting all the test methods.
#	Line 665 | Line 640 | public class CompletableFutureTest exten
640
641		ASYNC {
642		public void checkExecutionMode() {
643	<	assertSame(ForkJoinPool.commonPool(),
644	<	ForkJoinTask.getPool());
643	>	assertEquals(defaultExecutorIsCommonPool,
644	>	(ForkJoinPool.commonPool() == ForkJoinTask.getPool()));
645		}
646		public CompletableFuture<Void> runAsync(Runnable a) {
647		return CompletableFuture.runAsync(a);
#	Line 865 | Line 840 | public class CompletableFutureTest exten
840		if (!createIncomplete) assertTrue(f.complete(v1));
841		final CompletableFuture<Integer> g = f.exceptionally
842		((Throwable t) -> {
868	–	// Should not be called
843		a.getAndIncrement();
844	<	throw new AssertionError();
844	>	threadFail("should not be called");
845	>	return null;            // unreached
846		});
847		if (createIncomplete) assertTrue(f.complete(v1));
848
#	Line 901 | Line 876 | public class CompletableFutureTest exten
876		assertEquals(1, a.get());
877		}}
878
879	+	/**
880	+	* If an "exceptionally action" throws an exception, it completes
881	+	* exceptionally with that exception
882	+	*/
883		public void testExceptionally_exceptionalCompletionActionFailed() {
884		for (boolean createIncomplete : new boolean[] { true, false })
906	–	for (Integer v1 : new Integer[] { 1, null })
885		{
886		final AtomicInteger a = new AtomicInteger(0);
887		final CFException ex1 = new CFException();
#	Line 920 | Line 898 | public class CompletableFutureTest exten
898		if (createIncomplete) f.completeExceptionally(ex1);
899
900		checkCompletedWithWrappedException(g, ex2);
901	+	checkCompletedExceptionally(f, ex1);
902		assertEquals(1, a.get());
903		}}
904
#	Line 927 | Line 906 | public class CompletableFutureTest exten
906		* whenComplete action executes on normal completion, propagating
907		* source result.
908		*/
909	<	public void testWhenComplete_normalCompletion1() {
909	>	public void testWhenComplete_normalCompletion() {
910		for (ExecutionMode m : ExecutionMode.values())
911		for (boolean createIncomplete : new boolean[] { true, false })
912		for (Integer v1 : new Integer[] { 1, null })
#	Line 937 | Line 916 | public class CompletableFutureTest exten
916		if (!createIncomplete) assertTrue(f.complete(v1));
917		final CompletableFuture<Integer> g = m.whenComplete
918		(f,
919	<	(Integer x, Throwable t) -> {
919	>	(Integer result, Throwable t) -> {
920		m.checkExecutionMode();
921	<	threadAssertSame(x, v1);
921	>	threadAssertSame(result, v1);
922		threadAssertNull(t);
923		a.getAndIncrement();
924		});
#	Line 957 | Line 936 | public class CompletableFutureTest exten
936		public void testWhenComplete_exceptionalCompletion() {
937		for (ExecutionMode m : ExecutionMode.values())
938		for (boolean createIncomplete : new boolean[] { true, false })
960	–	for (Integer v1 : new Integer[] { 1, null })
939		{
940		final AtomicInteger a = new AtomicInteger(0);
941		final CFException ex = new CFException();
#	Line 965 | Line 943 | public class CompletableFutureTest exten
943		if (!createIncomplete) f.completeExceptionally(ex);
944		final CompletableFuture<Integer> g = m.whenComplete
945		(f,
946	<	(Integer x, Throwable t) -> {
946	>	(Integer result, Throwable t) -> {
947		m.checkExecutionMode();
948	<	threadAssertNull(x);
948	>	threadAssertNull(result);
949		threadAssertSame(t, ex);
950		a.getAndIncrement();
951		});
#	Line 992 | Line 970 | public class CompletableFutureTest exten
970		if (!createIncomplete) assertTrue(f.cancel(mayInterruptIfRunning));
971		final CompletableFuture<Integer> g = m.whenComplete
972		(f,
973	<	(Integer x, Throwable t) -> {
973	>	(Integer result, Throwable t) -> {
974		m.checkExecutionMode();
975	<	threadAssertNull(x);
975	>	threadAssertNull(result);
976		threadAssertTrue(t instanceof CancellationException);
977		a.getAndIncrement();
978		});
#	Line 1009 | Line 987 | public class CompletableFutureTest exten
987		* If a whenComplete action throws an exception when triggered by
988		* a normal completion, it completes exceptionally
989		*/
990	<	public void testWhenComplete_actionFailed() {
990	>	public void testWhenComplete_sourceCompletedNormallyActionFailed() {
991		for (boolean createIncomplete : new boolean[] { true, false })
992		for (ExecutionMode m : ExecutionMode.values())
993		for (Integer v1 : new Integer[] { 1, null })
#	Line 1020 | Line 998 | public class CompletableFutureTest exten
998		if (!createIncomplete) assertTrue(f.complete(v1));
999		final CompletableFuture<Integer> g = m.whenComplete
1000		(f,
1001	<	(Integer x, Throwable t) -> {
1001	>	(Integer result, Throwable t) -> {
1002		m.checkExecutionMode();
1003	<	threadAssertSame(x, v1);
1003	>	threadAssertSame(result, v1);
1004		threadAssertNull(t);
1005		a.getAndIncrement();
1006		throw ex;
#	Line 1037 | Line 1015 | public class CompletableFutureTest exten
1015		/**
1016		* If a whenComplete action throws an exception when triggered by
1017		* a source completion that also throws an exception, the source
1018	<	* exception takes precedence.
1018	>	* exception takes precedence (unlike handle)
1019		*/
1020	<	public void testWhenComplete_actionFailedSourceFailed() {
1020	>	public void testWhenComplete_sourceFailedActionFailed() {
1021		for (boolean createIncomplete : new boolean[] { true, false })
1022		for (ExecutionMode m : ExecutionMode.values())
1045	–	for (Integer v1 : new Integer[] { 1, null })
1023		{
1024		final AtomicInteger a = new AtomicInteger(0);
1025		final CFException ex1 = new CFException();
#	Line 1052 | Line 1029 | public class CompletableFutureTest exten
1029		if (!createIncomplete) f.completeExceptionally(ex1);
1030		final CompletableFuture<Integer> g = m.whenComplete
1031		(f,
1032	<	(Integer x, Throwable t) -> {
1032	>	(Integer result, Throwable t) -> {
1033		m.checkExecutionMode();
1034		threadAssertSame(t, ex1);
1035	<	threadAssertNull(x);
1035	>	threadAssertNull(result);
1036		a.getAndIncrement();
1037		throw ex2;
1038		});
#	Line 1063 | Line 1040 | public class CompletableFutureTest exten
1040
1041		checkCompletedWithWrappedException(g, ex1);
1042		checkCompletedExceptionally(f, ex1);
1043	+	if (testImplementationDetails) {
1044	+	assertEquals(1, ex1.getSuppressed().length);
1045	+	assertSame(ex2, ex1.getSuppressed()[0]);
1046	+	}
1047		assertEquals(1, a.get());
1048		}}
1049
#	Line 1080 | Line 1061 | public class CompletableFutureTest exten
1061		if (!createIncomplete) assertTrue(f.complete(v1));
1062		final CompletableFuture<Integer> g = m.handle
1063		(f,
1064	<	(Integer x, Throwable t) -> {
1064	>	(Integer result, Throwable t) -> {
1065		m.checkExecutionMode();
1066	<	threadAssertSame(x, v1);
1066	>	threadAssertSame(result, v1);
1067		threadAssertNull(t);
1068		a.getAndIncrement();
1069		return inc(v1);
#	Line 1109 | Line 1090 | public class CompletableFutureTest exten
1090		if (!createIncomplete) f.completeExceptionally(ex);
1091		final CompletableFuture<Integer> g = m.handle
1092		(f,
1093	<	(Integer x, Throwable t) -> {
1093	>	(Integer result, Throwable t) -> {
1094		m.checkExecutionMode();
1095	<	threadAssertNull(x);
1095	>	threadAssertNull(result);
1096		threadAssertSame(t, ex);
1097		a.getAndIncrement();
1098		return v1;
#	Line 1138 | Line 1119 | public class CompletableFutureTest exten
1119		if (!createIncomplete) assertTrue(f.cancel(mayInterruptIfRunning));
1120		final CompletableFuture<Integer> g = m.handle
1121		(f,
1122	<	(Integer x, Throwable t) -> {
1122	>	(Integer result, Throwable t) -> {
1123		m.checkExecutionMode();
1124	<	threadAssertNull(x);
1124	>	threadAssertNull(result);
1125		threadAssertTrue(t instanceof CancellationException);
1126		a.getAndIncrement();
1127		return v1;
#	Line 1153 | Line 1134 | public class CompletableFutureTest exten
1134		}}
1135
1136		/**
1137	<	* handle result completes exceptionally if action does
1137	>	* If a "handle action" throws an exception when triggered by
1138	>	* a normal completion, it completes exceptionally
1139		*/
1140	<	public void testHandle_sourceFailedActionFailed() {
1140	>	public void testHandle_sourceCompletedNormallyActionFailed() {
1141		for (ExecutionMode m : ExecutionMode.values())
1142		for (boolean createIncomplete : new boolean[] { true, false })
1143	+	for (Integer v1 : new Integer[] { 1, null })
1144		{
1145		final CompletableFuture<Integer> f = new CompletableFuture<>();
1146		final AtomicInteger a = new AtomicInteger(0);
1147	<	final CFException ex1 = new CFException();
1148	<	final CFException ex2 = new CFException();
1166	<	if (!createIncomplete) f.completeExceptionally(ex1);
1147	>	final CFException ex = new CFException();
1148	>	if (!createIncomplete) assertTrue(f.complete(v1));
1149		final CompletableFuture<Integer> g = m.handle
1150		(f,
1151	<	(Integer x, Throwable t) -> {
1151	>	(Integer result, Throwable t) -> {
1152		m.checkExecutionMode();
1153	<	threadAssertNull(x);
1154	<	threadAssertSame(ex1, t);
1153	>	threadAssertSame(result, v1);
1154	>	threadAssertNull(t);
1155		a.getAndIncrement();
1156	<	throw ex2;
1156	>	throw ex;
1157		});
1158	<	if (createIncomplete) f.completeExceptionally(ex1);
1158	>	if (createIncomplete) assertTrue(f.complete(v1));
1159
1160	<	checkCompletedWithWrappedException(g, ex2);
1161	<	checkCompletedExceptionally(f, ex1);
1160	>	checkCompletedWithWrappedException(g, ex);
1161	>	checkCompletedNormally(f, v1);
1162		assertEquals(1, a.get());
1163		}}
1164
1165	<	public void testHandle_sourceCompletedNormallyActionFailed() {
1166	<	for (ExecutionMode m : ExecutionMode.values())
1165	>	/**
1166	>	* If a "handle action" throws an exception when triggered by
1167	>	* a source completion that also throws an exception, the action
1168	>	* exception takes precedence (unlike whenComplete)
1169	>	*/
1170	>	public void testHandle_sourceFailedActionFailed() {
1171		for (boolean createIncomplete : new boolean[] { true, false })
1172	<	for (Integer v1 : new Integer[] { 1, null })
1172	>	for (ExecutionMode m : ExecutionMode.values())
1173		{
1188	–	final CompletableFuture<Integer> f = new CompletableFuture<>();
1174		final AtomicInteger a = new AtomicInteger(0);
1175	<	final CFException ex = new CFException();
1176	<	if (!createIncomplete) assertTrue(f.complete(v1));
1175	>	final CFException ex1 = new CFException();
1176	>	final CFException ex2 = new CFException();
1177	>	final CompletableFuture<Integer> f = new CompletableFuture<>();
1178	>
1179	>	if (!createIncomplete) f.completeExceptionally(ex1);
1180		final CompletableFuture<Integer> g = m.handle
1181		(f,
1182	<	(Integer x, Throwable t) -> {
1182	>	(Integer result, Throwable t) -> {
1183		m.checkExecutionMode();
1184	<	threadAssertSame(x, v1);
1185	<	threadAssertNull(t);
1184	>	threadAssertNull(result);
1185	>	threadAssertSame(ex1, t);
1186		a.getAndIncrement();
1187	<	throw ex;
1187	>	throw ex2;
1188		});
1189	<	if (createIncomplete) assertTrue(f.complete(v1));
1189	>	if (createIncomplete) f.completeExceptionally(ex1);
1190
1191	<	checkCompletedWithWrappedException(g, ex);
1192	<	checkCompletedNormally(f, v1);
1191	>	checkCompletedWithWrappedException(g, ex2);
1192	>	checkCompletedExceptionally(f, ex1);
1193		assertEquals(1, a.get());
1194		}}
1195
#	Line 2990 | Line 2978 | public class CompletableFutureTest exten
2978		checkCancelled(f);
2979		}}
2980
2981	+	/**
2982	+	* thenCompose result completes exceptionally if the result of the action does
2983	+	*/
2984	+	public void testThenCompose_actionReturnsFailingFuture() {
2985	+	for (ExecutionMode m : ExecutionMode.values())
2986	+	for (int order = 0; order < 6; order++)
2987	+	for (Integer v1 : new Integer[] { 1, null })
2988	+	{
2989	+	final CFException ex = new CFException();
2990	+	final CompletableFuture<Integer> f = new CompletableFuture<>();
2991	+	final CompletableFuture<Integer> g = new CompletableFuture<>();
2992	+	final CompletableFuture<Integer> h;
2993	+	// Test all permutations of orders
2994	+	switch (order) {
2995	+	case 0:
2996	+	assertTrue(f.complete(v1));
2997	+	assertTrue(g.completeExceptionally(ex));
2998	+	h = m.thenCompose(f, (x -> g));
2999	+	break;
3000	+	case 1:
3001	+	assertTrue(f.complete(v1));
3002	+	h = m.thenCompose(f, (x -> g));
3003	+	assertTrue(g.completeExceptionally(ex));
3004	+	break;
3005	+	case 2:
3006	+	assertTrue(g.completeExceptionally(ex));
3007	+	assertTrue(f.complete(v1));
3008	+	h = m.thenCompose(f, (x -> g));
3009	+	break;
3010	+	case 3:
3011	+	assertTrue(g.completeExceptionally(ex));
3012	+	h = m.thenCompose(f, (x -> g));
3013	+	assertTrue(f.complete(v1));
3014	+	break;
3015	+	case 4:
3016	+	h = m.thenCompose(f, (x -> g));
3017	+	assertTrue(f.complete(v1));
3018	+	assertTrue(g.completeExceptionally(ex));
3019	+	break;
3020	+	case 5:
3021	+	h = m.thenCompose(f, (x -> g));
3022	+	assertTrue(f.complete(v1));
3023	+	assertTrue(g.completeExceptionally(ex));
3024	+	break;
3025	+	default: throw new AssertionError();
3026	+	}
3027	+
3028	+	checkCompletedExceptionally(g, ex);
3029	+	checkCompletedWithWrappedException(h, ex);
3030	+	checkCompletedNormally(f, v1);
3031	+	}}
3032	+
3033		// other static methods
3034
3035		/**
#	Line 3050 | Line 3090 | public class CompletableFutureTest exten
3090		for (int i = 0; i < k; i++) {
3091		checkIncomplete(f);
3092		checkIncomplete(CompletableFuture.allOf(fs));
3093	<	if (i != k/2) {
3093	>	if (i != k / 2) {
3094		fs[i].complete(i);
3095		checkCompletedNormally(fs[i], i);
3096		} else {
#	Line 3157 | Line 3197 | public class CompletableFutureTest exten
3197		CompletableFuture<Integer> f = new CompletableFuture<>();
3198		CompletableFuture<Integer> g = new CompletableFuture<>();
3199		CompletableFuture<Integer> nullFuture = (CompletableFuture<Integer>)null;
3160	–	CompletableFuture<?> h;
3200		ThreadExecutor exec = new ThreadExecutor();
3201
3202		Runnable[] throwingActions = {
#	Line 3254 | Line 3293 | public class CompletableFutureTest exten
3293		() -> CompletableFuture.anyOf(null, f),
3294
3295		() -> f.obtrudeException(null),
3296	+
3297	+	() -> CompletableFuture.delayedExecutor(1L, SECONDS, null),
3298	+	() -> CompletableFuture.delayedExecutor(1L, null, new ThreadExecutor()),
3299	+	() -> CompletableFuture.delayedExecutor(1L, null),
3300	+
3301	+	() -> f.orTimeout(1L, null),
3302	+	() -> f.completeOnTimeout(42, 1L, null),
3303	+
3304	+	() -> CompletableFuture.failedFuture(null),
3305	+	() -> CompletableFuture.failedStage(null),
3306		};
3307
3308		assertThrows(NullPointerException.class, throwingActions);
#	Line 3268 | Line 3317 | public class CompletableFutureTest exten
3317		assertSame(f, f.toCompletableFuture());
3318		}
3319
3320	+	// jdk9
3321	+
3322	+	/**
3323	+	* newIncompleteFuture returns an incomplete CompletableFuture
3324	+	*/
3325	+	public void testNewIncompleteFuture() {
3326	+	for (Integer v1 : new Integer[] { 1, null })
3327	+	{
3328	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3329	+	CompletableFuture<Integer> g = f.newIncompleteFuture();
3330	+	checkIncomplete(f);
3331	+	checkIncomplete(g);
3332	+	f.complete(v1);
3333	+	checkCompletedNormally(f, v1);
3334	+	checkIncomplete(g);
3335	+	g.complete(v1);
3336	+	checkCompletedNormally(g, v1);
3337	+	assertSame(g.getClass(), CompletableFuture.class);
3338	+	}}
3339	+
3340	+	/**
3341	+	* completedStage returns a completed CompletionStage
3342	+	*/
3343	+	public void testCompletedStage() {
3344	+	AtomicInteger x = new AtomicInteger(0);
3345	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3346	+	CompletionStage<Integer> f = CompletableFuture.completedStage(1);
3347	+	f.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3348	+	assertEquals(x.get(), 1);
3349	+	assertNull(r.get());
3350	+	}
3351	+
3352	+	/**
3353	+	* defaultExecutor by default returns the commonPool if
3354	+	* it supports more than one thread.
3355	+	*/
3356	+	public void testDefaultExecutor() {
3357	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3358	+	Executor e = f.defaultExecutor();
3359	+	Executor c = ForkJoinPool.commonPool();
3360	+	if (ForkJoinPool.getCommonPoolParallelism() > 1)
3361	+	assertSame(e, c);
3362	+	else
3363	+	assertNotSame(e, c);
3364	+	}
3365	+
3366	+	/**
3367	+	* failedFuture returns a CompletableFuture completed
3368	+	* exceptionally with the given Exception
3369	+	*/
3370	+	public void testFailedFuture() {
3371	+	CFException ex = new CFException();
3372	+	CompletableFuture<Integer> f = CompletableFuture.failedFuture(ex);
3373	+	checkCompletedExceptionally(f, ex);
3374	+	}
3375	+
3376	+	/**
3377	+	* failedFuture(null) throws NPE
3378	+	*/
3379	+	public void testFailedFuture_null() {
3380	+	try {
3381	+	CompletableFuture<Integer> f = CompletableFuture.failedFuture(null);
3382	+	shouldThrow();
3383	+	} catch (NullPointerException success) {}
3384	+	}
3385	+
3386	+	/**
3387	+	* copy returns a CompletableFuture that is completed normally,
3388	+	* with the same value, when source is.
3389	+	*/
3390	+	public void testCopy() {
3391	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3392	+	CompletableFuture<Integer> g = f.copy();
3393	+	checkIncomplete(f);
3394	+	checkIncomplete(g);
3395	+	f.complete(1);
3396	+	checkCompletedNormally(f, 1);
3397	+	checkCompletedNormally(g, 1);
3398	+	}
3399	+
3400	+	/**
3401	+	* copy returns a CompletableFuture that is completed exceptionally
3402	+	* when source is.
3403	+	*/
3404	+	public void testCopy2() {
3405	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3406	+	CompletableFuture<Integer> g = f.copy();
3407	+	checkIncomplete(f);
3408	+	checkIncomplete(g);
3409	+	CFException ex = new CFException();
3410	+	f.completeExceptionally(ex);
3411	+	checkCompletedExceptionally(f, ex);
3412	+	checkCompletedWithWrappedException(g, ex);
3413	+	}
3414	+
3415	+	/**
3416	+	* minimalCompletionStage returns a CompletableFuture that is
3417	+	* completed normally, with the same value, when source is.
3418	+	*/
3419	+	public void testMinimalCompletionStage() {
3420	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3421	+	CompletionStage<Integer> g = f.minimalCompletionStage();
3422	+	AtomicInteger x = new AtomicInteger(0);
3423	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3424	+	checkIncomplete(f);
3425	+	g.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3426	+	f.complete(1);
3427	+	checkCompletedNormally(f, 1);
3428	+	assertEquals(x.get(), 1);
3429	+	assertNull(r.get());
3430	+	}
3431	+
3432	+	/**
3433	+	* minimalCompletionStage returns a CompletableFuture that is
3434	+	* completed exceptionally when source is.
3435	+	*/
3436	+	public void testMinimalCompletionStage2() {
3437	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3438	+	CompletionStage<Integer> g = f.minimalCompletionStage();
3439	+	AtomicInteger x = new AtomicInteger(0);
3440	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3441	+	g.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3442	+	checkIncomplete(f);
3443	+	CFException ex = new CFException();
3444	+	f.completeExceptionally(ex);
3445	+	checkCompletedExceptionally(f, ex);
3446	+	assertEquals(x.get(), 0);
3447	+	assertEquals(r.get().getCause(), ex);
3448	+	}
3449	+
3450	+	/**
3451	+	* failedStage returns a CompletionStage completed
3452	+	* exceptionally with the given Exception
3453	+	*/
3454	+	public void testFailedStage() {
3455	+	CFException ex = new CFException();
3456	+	CompletionStage<Integer> f = CompletableFuture.failedStage(ex);
3457	+	AtomicInteger x = new AtomicInteger(0);
3458	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3459	+	f.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3460	+	assertEquals(x.get(), 0);
3461	+	assertEquals(r.get(), ex);
3462	+	}
3463	+
3464	+	/**
3465	+	* completeAsync completes with value of given supplier
3466	+	*/
3467	+	public void testCompleteAsync() {
3468	+	for (Integer v1 : new Integer[] { 1, null })
3469	+	{
3470	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3471	+	f.completeAsync(() -> v1);
3472	+	f.join();
3473	+	checkCompletedNormally(f, v1);
3474	+	}}
3475	+
3476	+	/**
3477	+	* completeAsync completes exceptionally if given supplier throws
3478	+	*/
3479	+	public void testCompleteAsync2() {
3480	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3481	+	CFException ex = new CFException();
3482	+	f.completeAsync(() -> {if (true) throw ex; return 1;});
3483	+	try {
3484	+	f.join();
3485	+	shouldThrow();
3486	+	} catch (CompletionException success) {}
3487	+	checkCompletedWithWrappedException(f, ex);
3488	+	}
3489	+
3490	+	/**
3491	+	* completeAsync with given executor completes with value of given supplier
3492	+	*/
3493	+	public void testCompleteAsync3() {
3494	+	for (Integer v1 : new Integer[] { 1, null })
3495	+	{
3496	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3497	+	ThreadExecutor executor = new ThreadExecutor();
3498	+	f.completeAsync(() -> v1, executor);
3499	+	assertSame(v1, f.join());
3500	+	checkCompletedNormally(f, v1);
3501	+	assertEquals(1, executor.count.get());
3502	+	}}
3503	+
3504	+	/**
3505	+	* completeAsync with given executor completes exceptionally if
3506	+	* given supplier throws
3507	+	*/
3508	+	public void testCompleteAsync4() {
3509	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3510	+	CFException ex = new CFException();
3511	+	ThreadExecutor executor = new ThreadExecutor();
3512	+	f.completeAsync(() -> {if (true) throw ex; return 1;}, executor);
3513	+	try {
3514	+	f.join();
3515	+	shouldThrow();
3516	+	} catch (CompletionException success) {}
3517	+	checkCompletedWithWrappedException(f, ex);
3518	+	assertEquals(1, executor.count.get());
3519	+	}
3520	+
3521	+	/**
3522	+	* orTimeout completes with TimeoutException if not complete
3523	+	*/
3524	+	public void testOrTimeout_timesOut() {
3525	+	long timeoutMillis = timeoutMillis();
3526	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3527	+	long startTime = System.nanoTime();
3528	+	f.orTimeout(timeoutMillis, MILLISECONDS);
3529	+	checkCompletedWithTimeoutException(f);
3530	+	assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
3531	+	}
3532	+
3533	+	/**
3534	+	* orTimeout completes normally if completed before timeout
3535	+	*/
3536	+	public void testOrTimeout_completed() {
3537	+	for (Integer v1 : new Integer[] { 1, null })
3538	+	{
3539	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3540	+	CompletableFuture<Integer> g = new CompletableFuture<>();
3541	+	long startTime = System.nanoTime();
3542	+	f.complete(v1);
3543	+	f.orTimeout(LONG_DELAY_MS, MILLISECONDS);
3544	+	g.orTimeout(LONG_DELAY_MS, MILLISECONDS);
3545	+	g.complete(v1);
3546	+	checkCompletedNormally(f, v1);
3547	+	checkCompletedNormally(g, v1);
3548	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS / 2);
3549	+	}}
3550	+
3551	+	/**
3552	+	* completeOnTimeout completes with given value if not complete
3553	+	*/
3554	+	public void testCompleteOnTimeout_timesOut() {
3555	+	testInParallel(() -> testCompleteOnTimeout_timesOut(42),
3556	+	() -> testCompleteOnTimeout_timesOut(null));
3557	+	}
3558	+
3559	+	public void testCompleteOnTimeout_timesOut(Integer v) {
3560	+	long timeoutMillis = timeoutMillis();
3561	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3562	+	long startTime = System.nanoTime();
3563	+	f.completeOnTimeout(v, timeoutMillis, MILLISECONDS);
3564	+	assertSame(v, f.join());
3565	+	assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
3566	+	f.complete(99);         // should have no effect
3567	+	checkCompletedNormally(f, v);
3568	+	}
3569	+
3570	+	/**
3571	+	* completeOnTimeout has no effect if completed within timeout
3572	+	*/
3573	+	public void testCompleteOnTimeout_completed() {
3574	+	for (Integer v1 : new Integer[] { 1, null })
3575	+	{
3576	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3577	+	CompletableFuture<Integer> g = new CompletableFuture<>();
3578	+	long startTime = System.nanoTime();
3579	+	f.complete(v1);
3580	+	f.completeOnTimeout(-1, LONG_DELAY_MS, MILLISECONDS);
3581	+	g.completeOnTimeout(-1, LONG_DELAY_MS, MILLISECONDS);
3582	+	g.complete(v1);
3583	+	checkCompletedNormally(f, v1);
3584	+	checkCompletedNormally(g, v1);
3585	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS / 2);
3586	+	}}
3587	+
3588	+	/**
3589	+	* delayedExecutor returns an executor that delays submission
3590	+	*/
3591	+	public void testDelayedExecutor() {
3592	+	testInParallel(() -> testDelayedExecutor(null, null),
3593	+	() -> testDelayedExecutor(null, 1),
3594	+	() -> testDelayedExecutor(new ThreadExecutor(), 1),
3595	+	() -> testDelayedExecutor(new ThreadExecutor(), 1));
3596	+	}
3597	+
3598	+	public void testDelayedExecutor(Executor executor, Integer v) throws Exception {
3599	+	long timeoutMillis = timeoutMillis();
3600	+	// Use an "unreasonably long" long timeout to catch lingering threads
3601	+	long longTimeoutMillis = 1000 * 60 * 60 * 24;
3602	+	final Executor delayer, longDelayer;
3603	+	if (executor == null) {
3604	+	delayer = CompletableFuture.delayedExecutor(timeoutMillis, MILLISECONDS);
3605	+	longDelayer = CompletableFuture.delayedExecutor(longTimeoutMillis, MILLISECONDS);
3606	+	} else {
3607	+	delayer = CompletableFuture.delayedExecutor(timeoutMillis, MILLISECONDS, executor);
3608	+	longDelayer = CompletableFuture.delayedExecutor(longTimeoutMillis, MILLISECONDS, executor);
3609	+	}
3610	+	long startTime = System.nanoTime();
3611	+	CompletableFuture<Integer> f =
3612	+	CompletableFuture.supplyAsync(() -> v, delayer);
3613	+	CompletableFuture<Integer> g =
3614	+	CompletableFuture.supplyAsync(() -> v, longDelayer);
3615	+
3616	+	assertNull(g.getNow(null));
3617	+
3618	+	assertSame(v, f.get(LONG_DELAY_MS, MILLISECONDS));
3619	+	long millisElapsed = millisElapsedSince(startTime);
3620	+	assertTrue(millisElapsed >= timeoutMillis);
3621	+	assertTrue(millisElapsed < LONG_DELAY_MS / 2);
3622	+
3623	+	checkCompletedNormally(f, v);
3624	+
3625	+	checkIncomplete(g);
3626	+	assertTrue(g.cancel(true));
3627	+	}
3628	+
3629		//--- tests of implementation details; not part of official tck ---
3630
3631		Object resultOf(CompletableFuture<?> f) {
#	Line 3302 | Line 3660 | public class CompletableFutureTest exten
3660		funs.add((y) -> m.thenAcceptBoth(y, v42, new SubtractAction(m)));
3661		funs.add((y) -> m.thenCombine(y, v42, new SubtractFunction(m)));
3662
3663	<	funs.add((y) -> m.whenComplete(y, (Integer x, Throwable t) -> {}));
3663	>	funs.add((y) -> m.whenComplete(y, (Integer r, Throwable t) -> {}));
3664
3665		funs.add((y) -> m.thenCompose(y, new CompletableFutureInc(m)));
3666
#	Line 3358 | Line 3716 | public class CompletableFutureTest exten
3716		}
3717		}}
3718
3719	+	/**
3720	+	* Minimal completion stages throw UOE for all non-CompletionStage methods
3721	+	*/
3722	+	public void testMinimalCompletionStage_minimality() {
3723	+	if (!testImplementationDetails) return;
3724	+	Function<Method, String> toSignature =
3725	+	(method) -> method.getName() + Arrays.toString(method.getParameterTypes());
3726	+	Predicate<Method> isNotStatic =
3727	+	(method) -> (method.getModifiers() & Modifier.STATIC) == 0;
3728	+	List<Method> minimalMethods =
3729	+	Stream.of(Object.class, CompletionStage.class)
3730	+	.flatMap((klazz) -> Stream.of(klazz.getMethods()))
3731	+	.filter(isNotStatic)
3732	+	.collect(Collectors.toList());
3733	+	// Methods from CompletableFuture permitted NOT to throw UOE
3734	+	String[] signatureWhitelist = {
3735	+	"newIncompleteFuture[]",
3736	+	"defaultExecutor[]",
3737	+	"minimalCompletionStage[]",
3738	+	"copy[]",
3739	+	};
3740	+	Set<String> permittedMethodSignatures =
3741	+	Stream.concat(minimalMethods.stream().map(toSignature),
3742	+	Stream.of(signatureWhitelist))
3743	+	.collect(Collectors.toSet());
3744	+	List<Method> allMethods = Stream.of(CompletableFuture.class.getMethods())
3745	+	.filter(isNotStatic)
3746	+	.filter((method) -> !permittedMethodSignatures.contains(toSignature.apply(method)))
3747	+	.collect(Collectors.toList());
3748	+
3749	+	CompletionStage<Integer> minimalStage =
3750	+	new CompletableFuture<Integer>().minimalCompletionStage();
3751	+
3752	+	List<Method> bugs = new ArrayList<>();
3753	+	for (Method method : allMethods) {
3754	+	Class<?>[] parameterTypes = method.getParameterTypes();
3755	+	Object[] args = new Object[parameterTypes.length];
3756	+	// Manufacture boxed primitives for primitive params
3757	+	for (int i = 0; i < args.length; i++) {
3758	+	Class<?> type = parameterTypes[i];
3759	+	if (parameterTypes[i] == boolean.class)
3760	+	args[i] = false;
3761	+	else if (parameterTypes[i] == int.class)
3762	+	args[i] = 0;
3763	+	else if (parameterTypes[i] == long.class)
3764	+	args[i] = 0L;
3765	+	}
3766	+	try {
3767	+	method.invoke(minimalStage, args);
3768	+	bugs.add(method);
3769	+	}
3770	+	catch (java.lang.reflect.InvocationTargetException expected) {
3771	+	if (! (expected.getCause() instanceof UnsupportedOperationException)) {
3772	+	bugs.add(method);
3773	+	// expected.getCause().printStackTrace();
3774	+	}
3775	+	}
3776	+	catch (ReflectiveOperationException bad) { throw new Error(bad); }
3777	+	}
3778	+	if (!bugs.isEmpty())
3779	+	throw new Error("Methods did not throw UOE: " + bugs.toString());
3780	+	}
3781	+
3782	+	static class Monad {
3783	+	static class ZeroException extends RuntimeException {
3784	+	public ZeroException() { super("monadic zero"); }
3785	+	}
3786	+	// "return", "unit"
3787	+	static <T> CompletableFuture<T> unit(T value) {
3788	+	return completedFuture(value);
3789	+	}
3790	+	// monadic zero ?
3791	+	static <T> CompletableFuture<T> zero() {
3792	+	return failedFuture(new ZeroException());
3793	+	}
3794	+	// >=>
3795	+	static <T,U,V> Function<T, CompletableFuture<V>> compose
3796	+	(Function<T, CompletableFuture<U>> f,
3797	+	Function<U, CompletableFuture<V>> g) {
3798	+	return (x) -> f.apply(x).thenCompose(g);
3799	+	}
3800	+
3801	+	static void assertZero(CompletableFuture<?> f) {
3802	+	try {
3803	+	f.getNow(null);
3804	+	throw new AssertionFailedError("should throw");
3805	+	} catch (CompletionException success) {
3806	+	assertTrue(success.getCause() instanceof ZeroException);
3807	+	}
3808	+	}
3809	+
3810	+	static <T> void assertFutureEquals(CompletableFuture<T> f,
3811	+	CompletableFuture<T> g) {
3812	+	T fval = null, gval = null;
3813	+	Throwable fex = null, gex = null;
3814	+
3815	+	try { fval = f.get(); }
3816	+	catch (ExecutionException ex) { fex = ex.getCause(); }
3817	+	catch (Throwable ex) { fex = ex; }
3818	+
3819	+	try { gval = g.get(); }
3820	+	catch (ExecutionException ex) { gex = ex.getCause(); }
3821	+	catch (Throwable ex) { gex = ex; }
3822	+
3823	+	if (fex != null || gex != null)
3824	+	assertSame(fex.getClass(), gex.getClass());
3825	+	else
3826	+	assertEquals(fval, gval);
3827	+	}
3828	+
3829	+	static class PlusFuture<T> extends CompletableFuture<T> {
3830	+	AtomicReference<Throwable> firstFailure = new AtomicReference<>(null);
3831	+	}
3832	+
3833	+	/** Implements "monadic plus". */
3834	+	static <T> CompletableFuture<T> plus(CompletableFuture<? extends T> f,
3835	+	CompletableFuture<? extends T> g) {
3836	+	PlusFuture<T> plus = new PlusFuture<T>();
3837	+	BiConsumer<T, Throwable> action = (T result, Throwable ex) -> {
3838	+	try {
3839	+	if (ex == null) {
3840	+	if (plus.complete(result))
3841	+	if (plus.firstFailure.get() != null)
3842	+	plus.firstFailure.set(null);
3843	+	}
3844	+	else if (plus.firstFailure.compareAndSet(null, ex)) {
3845	+	if (plus.isDone())
3846	+	plus.firstFailure.set(null);
3847	+	}
3848	+	else {
3849	+	// first failure has precedence
3850	+	Throwable first = plus.firstFailure.getAndSet(null);
3851	+
3852	+	// may fail with "Self-suppression not permitted"
3853	+	try { first.addSuppressed(ex); }
3854	+	catch (Exception ignored) {}
3855	+
3856	+	plus.completeExceptionally(first);
3857	+	}
3858	+	} catch (Throwable unexpected) {
3859	+	plus.completeExceptionally(unexpected);
3860	+	}
3861	+	};
3862	+	f.whenComplete(action);
3863	+	g.whenComplete(action);
3864	+	return plus;
3865	+	}
3866	+	}
3867	+
3868	+	/**
3869	+	* CompletableFuture is an additive monad - sort of.
3870	+	* https://en.wikipedia.org/wiki/Monad_(functional_programming)#Additive_monads
3871	+	*/
3872	+	public void testAdditiveMonad() throws Throwable {
3873	+	Function<Long, CompletableFuture<Long>> unit = Monad::unit;
3874	+	CompletableFuture<Long> zero = Monad.zero();
3875	+
3876	+	// Some mutually non-commutative functions
3877	+	Function<Long, CompletableFuture<Long>> triple
3878	+	= (x) -> Monad.unit(3 * x);
3879	+	Function<Long, CompletableFuture<Long>> inc
3880	+	= (x) -> Monad.unit(x + 1);
3881	+
3882	+	// unit is a right identity: m >>= unit === m
3883	+	Monad.assertFutureEquals(inc.apply(5L).thenCompose(unit),
3884	+	inc.apply(5L));
3885	+	// unit is a left identity: (unit x) >>= f === f x
3886	+	Monad.assertFutureEquals(unit.apply(5L).thenCompose(inc),
3887	+	inc.apply(5L));
3888	+
3889	+	// associativity: (m >>= f) >>= g === m >>= ( \x -> (f x >>= g) )
3890	+	Monad.assertFutureEquals(
3891	+	unit.apply(5L).thenCompose(inc).thenCompose(triple),
3892	+	unit.apply(5L).thenCompose((x) -> inc.apply(x).thenCompose(triple)));
3893	+
3894	+	// The case for CompletableFuture as an additive monad is weaker...
3895	+
3896	+	// zero is a monadic zero
3897	+	Monad.assertZero(zero);
3898	+
3899	+	// left zero: zero >>= f === zero
3900	+	Monad.assertZero(zero.thenCompose(inc));
3901	+	// right zero: f >>= (\x -> zero) === zero
3902	+	Monad.assertZero(inc.apply(5L).thenCompose((x) -> zero));
3903	+
3904	+	// f plus zero === f
3905	+	Monad.assertFutureEquals(Monad.unit(5L),
3906	+	Monad.plus(Monad.unit(5L), zero));
3907	+	// zero plus f === f
3908	+	Monad.assertFutureEquals(Monad.unit(5L),
3909	+	Monad.plus(zero, Monad.unit(5L)));
3910	+	// zero plus zero === zero
3911	+	Monad.assertZero(Monad.plus(zero, zero));
3912	+	{
3913	+	CompletableFuture<Long> f = Monad.plus(Monad.unit(5L),
3914	+	Monad.unit(8L));
3915	+	// non-determinism
3916	+	assertTrue(f.get() == 5L || f.get() == 8L);
3917	+	}
3918	+
3919	+	CompletableFuture<Long> godot = new CompletableFuture<>();
3920	+	// f plus godot === f (doesn't wait for godot)
3921	+	Monad.assertFutureEquals(Monad.unit(5L),
3922	+	Monad.plus(Monad.unit(5L), godot));
3923	+	// godot plus f === f (doesn't wait for godot)
3924	+	Monad.assertFutureEquals(Monad.unit(5L),
3925	+	Monad.plus(godot, Monad.unit(5L)));
3926	+	}
3927	+
3928	+	//     static <U> U join(CompletionStage<U> stage) {
3929	+	//         CompletableFuture<U> f = new CompletableFuture<>();
3930	+	//         stage.whenComplete((v, ex) -> {
3931	+	//             if (ex != null) f.completeExceptionally(ex); else f.complete(v);
3932	+	//         });
3933	+	//         return f.join();
3934	+	//     }
3935	+
3936	+	//     static <U> boolean isDone(CompletionStage<U> stage) {
3937	+	//         CompletableFuture<U> f = new CompletableFuture<>();
3938	+	//         stage.whenComplete((v, ex) -> {
3939	+	//             if (ex != null) f.completeExceptionally(ex); else f.complete(v);
3940	+	//         });
3941	+	//         return f.isDone();
3942	+	//     }
3943	+
3944	+	//     static <U> U join2(CompletionStage<U> stage) {
3945	+	//         return stage.toCompletableFuture().copy().join();
3946	+	//     }
3947	+
3948	+	//     static <U> boolean isDone2(CompletionStage<U> stage) {
3949	+	//         return stage.toCompletableFuture().copy().isDone();
3950	+	//     }
3951	+
3952		}

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