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root/jsr166/jsr166/src/test/tck/CompletableFutureTest.java

Comparing jsr166/src/test/tck/CompletableFutureTest.java (file contents):
Revision 1.96 by jsr166, Sat Nov 1 14:50:26 2014 UTC vs.
Revision 1.136 by jsr166, Sun Nov 15 20:17:11 2015 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 868 | Line 840 | public class CompletableFutureTest exten
840		if (!createIncomplete) assertTrue(f.complete(v1));
841		final CompletableFuture<Integer> g = f.exceptionally
842		((Throwable t) -> {
871	–	// 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 904 | 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 })
909	–	for (Integer v1 : new Integer[] { 1, null })
885		{
886		final AtomicInteger a = new AtomicInteger(0);
887		final CFException ex1 = new CFException();
#	Line 923 | 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 930 | 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 940 | 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 960 | 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 })
963	–	for (Integer v1 : new Integer[] { 1, null })
939		{
940		final AtomicInteger a = new AtomicInteger(0);
941		final CFException ex = new CFException();
#	Line 968 | 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 995 | 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 1012 | 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 1023 | 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 1040 | 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())
1048	–	for (Integer v1 : new Integer[] { 1, null })
1023		{
1024		final AtomicInteger a = new AtomicInteger(0);
1025		final CFException ex1 = new CFException();
#	Line 1055 | 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 1083 | Line 1057 | public class CompletableFutureTest exten
1057		if (!createIncomplete) assertTrue(f.complete(v1));
1058		final CompletableFuture<Integer> g = m.handle
1059		(f,
1060	<	(Integer x, Throwable t) -> {
1060	>	(Integer result, Throwable t) -> {
1061		m.checkExecutionMode();
1062	<	threadAssertSame(x, v1);
1062	>	threadAssertSame(result, v1);
1063		threadAssertNull(t);
1064		a.getAndIncrement();
1065		return inc(v1);
#	Line 1112 | Line 1086 | public class CompletableFutureTest exten
1086		if (!createIncomplete) f.completeExceptionally(ex);
1087		final CompletableFuture<Integer> g = m.handle
1088		(f,
1089	<	(Integer x, Throwable t) -> {
1089	>	(Integer result, Throwable t) -> {
1090		m.checkExecutionMode();
1091	<	threadAssertNull(x);
1091	>	threadAssertNull(result);
1092		threadAssertSame(t, ex);
1093		a.getAndIncrement();
1094		return v1;
#	Line 1141 | Line 1115 | public class CompletableFutureTest exten
1115		if (!createIncomplete) assertTrue(f.cancel(mayInterruptIfRunning));
1116		final CompletableFuture<Integer> g = m.handle
1117		(f,
1118	<	(Integer x, Throwable t) -> {
1118	>	(Integer result, Throwable t) -> {
1119		m.checkExecutionMode();
1120	<	threadAssertNull(x);
1120	>	threadAssertNull(result);
1121		threadAssertTrue(t instanceof CancellationException);
1122		a.getAndIncrement();
1123		return v1;
#	Line 1156 | Line 1130 | public class CompletableFutureTest exten
1130		}}
1131
1132		/**
1133	<	* handle result completes exceptionally if action does
1133	>	* If a "handle action" throws an exception when triggered by
1134	>	* a normal completion, it completes exceptionally
1135		*/
1136	<	public void testHandle_sourceFailedActionFailed() {
1136	>	public void testHandle_sourceCompletedNormallyActionFailed() {
1137		for (ExecutionMode m : ExecutionMode.values())
1138		for (boolean createIncomplete : new boolean[] { true, false })
1139	+	for (Integer v1 : new Integer[] { 1, null })
1140		{
1141		final CompletableFuture<Integer> f = new CompletableFuture<>();
1142		final AtomicInteger a = new AtomicInteger(0);
1143	<	final CFException ex1 = new CFException();
1144	<	final CFException ex2 = new CFException();
1169	<	if (!createIncomplete) f.completeExceptionally(ex1);
1143	>	final CFException ex = new CFException();
1144	>	if (!createIncomplete) assertTrue(f.complete(v1));
1145		final CompletableFuture<Integer> g = m.handle
1146		(f,
1147	<	(Integer x, Throwable t) -> {
1147	>	(Integer result, Throwable t) -> {
1148		m.checkExecutionMode();
1149	<	threadAssertNull(x);
1150	<	threadAssertSame(ex1, t);
1149	>	threadAssertSame(result, v1);
1150	>	threadAssertNull(t);
1151		a.getAndIncrement();
1152	<	throw ex2;
1152	>	throw ex;
1153		});
1154	<	if (createIncomplete) f.completeExceptionally(ex1);
1154	>	if (createIncomplete) assertTrue(f.complete(v1));
1155
1156	<	checkCompletedWithWrappedException(g, ex2);
1157	<	checkCompletedExceptionally(f, ex1);
1156	>	checkCompletedWithWrappedException(g, ex);
1157	>	checkCompletedNormally(f, v1);
1158		assertEquals(1, a.get());
1159		}}
1160
1161	<	public void testHandle_sourceCompletedNormallyActionFailed() {
1162	<	for (ExecutionMode m : ExecutionMode.values())
1161	>	/**
1162	>	* If a "handle action" throws an exception when triggered by
1163	>	* a source completion that also throws an exception, the action
1164	>	* exception takes precedence (unlike whenComplete)
1165	>	*/
1166	>	public void testHandle_sourceFailedActionFailed() {
1167		for (boolean createIncomplete : new boolean[] { true, false })
1168	<	for (Integer v1 : new Integer[] { 1, null })
1168	>	for (ExecutionMode m : ExecutionMode.values())
1169		{
1191	–	final CompletableFuture<Integer> f = new CompletableFuture<>();
1170		final AtomicInteger a = new AtomicInteger(0);
1171	<	final CFException ex = new CFException();
1172	<	if (!createIncomplete) assertTrue(f.complete(v1));
1171	>	final CFException ex1 = new CFException();
1172	>	final CFException ex2 = new CFException();
1173	>	final CompletableFuture<Integer> f = new CompletableFuture<>();
1174	>
1175	>	if (!createIncomplete) f.completeExceptionally(ex1);
1176		final CompletableFuture<Integer> g = m.handle
1177		(f,
1178	<	(Integer x, Throwable t) -> {
1178	>	(Integer result, Throwable t) -> {
1179		m.checkExecutionMode();
1180	<	threadAssertSame(x, v1);
1181	<	threadAssertNull(t);
1180	>	threadAssertNull(result);
1181	>	threadAssertSame(ex1, t);
1182		a.getAndIncrement();
1183	<	throw ex;
1183	>	throw ex2;
1184		});
1185	<	if (createIncomplete) assertTrue(f.complete(v1));
1185	>	if (createIncomplete) f.completeExceptionally(ex1);
1186
1187	<	checkCompletedWithWrappedException(g, ex);
1188	<	checkCompletedNormally(f, v1);
1187	>	checkCompletedWithWrappedException(g, ex2);
1188	>	checkCompletedExceptionally(f, ex1);
1189		assertEquals(1, a.get());
1190		}}
1191
#	Line 2993 | Line 2974 | public class CompletableFutureTest exten
2974		checkCancelled(f);
2975		}}
2976
2977	+	/**
2978	+	* thenCompose result completes exceptionally if the result of the action does
2979	+	*/
2980	+	public void testThenCompose_actionReturnsFailingFuture() {
2981	+	for (ExecutionMode m : ExecutionMode.values())
2982	+	for (int order = 0; order < 6; order++)
2983	+	for (Integer v1 : new Integer[] { 1, null })
2984	+	{
2985	+	final CFException ex = new CFException();
2986	+	final CompletableFuture<Integer> f = new CompletableFuture<>();
2987	+	final CompletableFuture<Integer> g = new CompletableFuture<>();
2988	+	final CompletableFuture<Integer> h;
2989	+	// Test all permutations of orders
2990	+	switch (order) {
2991	+	case 0:
2992	+	assertTrue(f.complete(v1));
2993	+	assertTrue(g.completeExceptionally(ex));
2994	+	h = m.thenCompose(f, (x -> g));
2995	+	break;
2996	+	case 1:
2997	+	assertTrue(f.complete(v1));
2998	+	h = m.thenCompose(f, (x -> g));
2999	+	assertTrue(g.completeExceptionally(ex));
3000	+	break;
3001	+	case 2:
3002	+	assertTrue(g.completeExceptionally(ex));
3003	+	assertTrue(f.complete(v1));
3004	+	h = m.thenCompose(f, (x -> g));
3005	+	break;
3006	+	case 3:
3007	+	assertTrue(g.completeExceptionally(ex));
3008	+	h = m.thenCompose(f, (x -> g));
3009	+	assertTrue(f.complete(v1));
3010	+	break;
3011	+	case 4:
3012	+	h = m.thenCompose(f, (x -> g));
3013	+	assertTrue(f.complete(v1));
3014	+	assertTrue(g.completeExceptionally(ex));
3015	+	break;
3016	+	case 5:
3017	+	h = m.thenCompose(f, (x -> g));
3018	+	assertTrue(f.complete(v1));
3019	+	assertTrue(g.completeExceptionally(ex));
3020	+	break;
3021	+	default: throw new AssertionError();
3022	+	}
3023	+
3024	+	checkCompletedExceptionally(g, ex);
3025	+	checkCompletedWithWrappedException(h, ex);
3026	+	checkCompletedNormally(f, v1);
3027	+	}}
3028	+
3029		// other static methods
3030
3031		/**
#	Line 3053 | Line 3086 | public class CompletableFutureTest exten
3086		for (int i = 0; i < k; i++) {
3087		checkIncomplete(f);
3088		checkIncomplete(CompletableFuture.allOf(fs));
3089	<	if (i != k/2) {
3089	>	if (i != k / 2) {
3090		fs[i].complete(i);
3091		checkCompletedNormally(fs[i], i);
3092		} else {
#	Line 3160 | Line 3193 | public class CompletableFutureTest exten
3193		CompletableFuture<Integer> f = new CompletableFuture<>();
3194		CompletableFuture<Integer> g = new CompletableFuture<>();
3195		CompletableFuture<Integer> nullFuture = (CompletableFuture<Integer>)null;
3163	–	CompletableFuture<?> h;
3196		ThreadExecutor exec = new ThreadExecutor();
3197
3198		Runnable[] throwingActions = {
#	Line 3257 | Line 3289 | public class CompletableFutureTest exten
3289		() -> CompletableFuture.anyOf(null, f),
3290
3291		() -> f.obtrudeException(null),
3292	+
3293	+	() -> CompletableFuture.delayedExecutor(1L, SECONDS, null),
3294	+	() -> CompletableFuture.delayedExecutor(1L, null, new ThreadExecutor()),
3295	+	() -> CompletableFuture.delayedExecutor(1L, null),
3296	+
3297	+	() -> f.orTimeout(1L, null),
3298	+	() -> f.completeOnTimeout(42, 1L, null),
3299	+
3300	+	() -> CompletableFuture.failedFuture(null),
3301	+	() -> CompletableFuture.failedStage(null),
3302		};
3303
3304		assertThrows(NullPointerException.class, throwingActions);
#	Line 3271 | Line 3313 | public class CompletableFutureTest exten
3313		assertSame(f, f.toCompletableFuture());
3314		}
3315
3316	+	// jdk9
3317	+
3318	+	/**
3319	+	* newIncompleteFuture returns an incomplete CompletableFuture
3320	+	*/
3321	+	public void testNewIncompleteFuture() {
3322	+	for (Integer v1 : new Integer[] { 1, null })
3323	+	{
3324	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3325	+	CompletableFuture<Integer> g = f.newIncompleteFuture();
3326	+	checkIncomplete(f);
3327	+	checkIncomplete(g);
3328	+	f.complete(v1);
3329	+	checkCompletedNormally(f, v1);
3330	+	checkIncomplete(g);
3331	+	g.complete(v1);
3332	+	checkCompletedNormally(g, v1);
3333	+	assertSame(g.getClass(), CompletableFuture.class);
3334	+	}}
3335	+
3336	+	/**
3337	+	* completedStage returns a completed CompletionStage
3338	+	*/
3339	+	public void testCompletedStage() {
3340	+	AtomicInteger x = new AtomicInteger(0);
3341	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3342	+	CompletionStage<Integer> f = CompletableFuture.completedStage(1);
3343	+	f.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3344	+	assertEquals(x.get(), 1);
3345	+	assertNull(r.get());
3346	+	}
3347	+
3348	+	/**
3349	+	* defaultExecutor by default returns the commonPool if
3350	+	* it supports more than one thread.
3351	+	*/
3352	+	public void testDefaultExecutor() {
3353	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3354	+	Executor e = f.defaultExecutor();
3355	+	Executor c = ForkJoinPool.commonPool();
3356	+	if (ForkJoinPool.getCommonPoolParallelism() > 1)
3357	+	assertSame(e, c);
3358	+	else
3359	+	assertNotSame(e, c);
3360	+	}
3361	+
3362	+	/**
3363	+	* failedFuture returns a CompletableFuture completed
3364	+	* exceptionally with the given Exception
3365	+	*/
3366	+	public void testFailedFuture() {
3367	+	CFException ex = new CFException();
3368	+	CompletableFuture<Integer> f = CompletableFuture.failedFuture(ex);
3369	+	checkCompletedExceptionally(f, ex);
3370	+	}
3371	+
3372	+	/**
3373	+	* failedFuture(null) throws NPE
3374	+	*/
3375	+	public void testFailedFuture_null() {
3376	+	try {
3377	+	CompletableFuture<Integer> f = CompletableFuture.failedFuture(null);
3378	+	shouldThrow();
3379	+	} catch (NullPointerException success) {}
3380	+	}
3381	+
3382	+	/**
3383	+	* copy returns a CompletableFuture that is completed normally,
3384	+	* with the same value, when source is.
3385	+	*/
3386	+	public void testCopy() {
3387	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3388	+	CompletableFuture<Integer> g = f.copy();
3389	+	checkIncomplete(f);
3390	+	checkIncomplete(g);
3391	+	f.complete(1);
3392	+	checkCompletedNormally(f, 1);
3393	+	checkCompletedNormally(g, 1);
3394	+	}
3395	+
3396	+	/**
3397	+	* copy returns a CompletableFuture that is completed exceptionally
3398	+	* when source is.
3399	+	*/
3400	+	public void testCopy2() {
3401	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3402	+	CompletableFuture<Integer> g = f.copy();
3403	+	checkIncomplete(f);
3404	+	checkIncomplete(g);
3405	+	CFException ex = new CFException();
3406	+	f.completeExceptionally(ex);
3407	+	checkCompletedExceptionally(f, ex);
3408	+	checkCompletedWithWrappedException(g, ex);
3409	+	}
3410	+
3411	+	/**
3412	+	* minimalCompletionStage returns a CompletableFuture that is
3413	+	* completed normally, with the same value, when source is.
3414	+	*/
3415	+	public void testMinimalCompletionStage() {
3416	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3417	+	CompletionStage<Integer> g = f.minimalCompletionStage();
3418	+	AtomicInteger x = new AtomicInteger(0);
3419	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3420	+	checkIncomplete(f);
3421	+	g.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3422	+	f.complete(1);
3423	+	checkCompletedNormally(f, 1);
3424	+	assertEquals(x.get(), 1);
3425	+	assertNull(r.get());
3426	+	}
3427	+
3428	+	/**
3429	+	* minimalCompletionStage returns a CompletableFuture that is
3430	+	* completed exceptionally when source is.
3431	+	*/
3432	+	public void testMinimalCompletionStage2() {
3433	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3434	+	CompletionStage<Integer> g = f.minimalCompletionStage();
3435	+	AtomicInteger x = new AtomicInteger(0);
3436	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3437	+	g.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3438	+	checkIncomplete(f);
3439	+	CFException ex = new CFException();
3440	+	f.completeExceptionally(ex);
3441	+	checkCompletedExceptionally(f, ex);
3442	+	assertEquals(x.get(), 0);
3443	+	assertEquals(r.get().getCause(), ex);
3444	+	}
3445	+
3446	+	/**
3447	+	* failedStage returns a CompletionStage completed
3448	+	* exceptionally with the given Exception
3449	+	*/
3450	+	public void testFailedStage() {
3451	+	CFException ex = new CFException();
3452	+	CompletionStage<Integer> f = CompletableFuture.failedStage(ex);
3453	+	AtomicInteger x = new AtomicInteger(0);
3454	+	AtomicReference<Throwable> r = new AtomicReference<Throwable>();
3455	+	f.whenComplete((v, e) -> {if (e != null) r.set(e); else x.set(v);});
3456	+	assertEquals(x.get(), 0);
3457	+	assertEquals(r.get(), ex);
3458	+	}
3459	+
3460	+	/**
3461	+	* completeAsync completes with value of given supplier
3462	+	*/
3463	+	public void testCompleteAsync() {
3464	+	for (Integer v1 : new Integer[] { 1, null })
3465	+	{
3466	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3467	+	f.completeAsync(() -> v1);
3468	+	f.join();
3469	+	checkCompletedNormally(f, v1);
3470	+	}}
3471	+
3472	+	/**
3473	+	* completeAsync completes exceptionally if given supplier throws
3474	+	*/
3475	+	public void testCompleteAsync2() {
3476	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3477	+	CFException ex = new CFException();
3478	+	f.completeAsync(() -> {if (true) throw ex; return 1;});
3479	+	try {
3480	+	f.join();
3481	+	shouldThrow();
3482	+	} catch (CompletionException success) {}
3483	+	checkCompletedWithWrappedException(f, ex);
3484	+	}
3485	+
3486	+	/**
3487	+	* completeAsync with given executor completes with value of given supplier
3488	+	*/
3489	+	public void testCompleteAsync3() {
3490	+	for (Integer v1 : new Integer[] { 1, null })
3491	+	{
3492	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3493	+	ThreadExecutor executor = new ThreadExecutor();
3494	+	f.completeAsync(() -> v1, executor);
3495	+	assertSame(v1, f.join());
3496	+	checkCompletedNormally(f, v1);
3497	+	assertEquals(1, executor.count.get());
3498	+	}}
3499	+
3500	+	/**
3501	+	* completeAsync with given executor completes exceptionally if
3502	+	* given supplier throws
3503	+	*/
3504	+	public void testCompleteAsync4() {
3505	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3506	+	CFException ex = new CFException();
3507	+	ThreadExecutor executor = new ThreadExecutor();
3508	+	f.completeAsync(() -> {if (true) throw ex; return 1;}, executor);
3509	+	try {
3510	+	f.join();
3511	+	shouldThrow();
3512	+	} catch (CompletionException success) {}
3513	+	checkCompletedWithWrappedException(f, ex);
3514	+	assertEquals(1, executor.count.get());
3515	+	}
3516	+
3517	+	/**
3518	+	* orTimeout completes with TimeoutException if not complete
3519	+	*/
3520	+	public void testOrTimeout_timesOut() {
3521	+	long timeoutMillis = timeoutMillis();
3522	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3523	+	long startTime = System.nanoTime();
3524	+	f.orTimeout(timeoutMillis, MILLISECONDS);
3525	+	checkCompletedWithTimeoutException(f);
3526	+	assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
3527	+	}
3528	+
3529	+	/**
3530	+	* orTimeout completes normally if completed before timeout
3531	+	*/
3532	+	public void testOrTimeout_completed() {
3533	+	for (Integer v1 : new Integer[] { 1, null })
3534	+	{
3535	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3536	+	CompletableFuture<Integer> g = new CompletableFuture<>();
3537	+	long startTime = System.nanoTime();
3538	+	f.complete(v1);
3539	+	f.orTimeout(LONG_DELAY_MS, MILLISECONDS);
3540	+	g.orTimeout(LONG_DELAY_MS, MILLISECONDS);
3541	+	g.complete(v1);
3542	+	checkCompletedNormally(f, v1);
3543	+	checkCompletedNormally(g, v1);
3544	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS / 2);
3545	+	}}
3546	+
3547	+	/**
3548	+	* completeOnTimeout completes with given value if not complete
3549	+	*/
3550	+	public void testCompleteOnTimeout_timesOut() {
3551	+	testInParallel(() -> testCompleteOnTimeout_timesOut(42),
3552	+	() -> testCompleteOnTimeout_timesOut(null));
3553	+	}
3554	+
3555	+	public void testCompleteOnTimeout_timesOut(Integer v) {
3556	+	long timeoutMillis = timeoutMillis();
3557	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3558	+	long startTime = System.nanoTime();
3559	+	f.completeOnTimeout(v, timeoutMillis, MILLISECONDS);
3560	+	assertSame(v, f.join());
3561	+	assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
3562	+	f.complete(99);         // should have no effect
3563	+	checkCompletedNormally(f, v);
3564	+	}
3565	+
3566	+	/**
3567	+	* completeOnTimeout has no effect if completed within timeout
3568	+	*/
3569	+	public void testCompleteOnTimeout_completed() {
3570	+	for (Integer v1 : new Integer[] { 1, null })
3571	+	{
3572	+	CompletableFuture<Integer> f = new CompletableFuture<>();
3573	+	CompletableFuture<Integer> g = new CompletableFuture<>();
3574	+	long startTime = System.nanoTime();
3575	+	f.complete(v1);
3576	+	f.completeOnTimeout(-1, LONG_DELAY_MS, MILLISECONDS);
3577	+	g.completeOnTimeout(-1, LONG_DELAY_MS, MILLISECONDS);
3578	+	g.complete(v1);
3579	+	checkCompletedNormally(f, v1);
3580	+	checkCompletedNormally(g, v1);
3581	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS / 2);
3582	+	}}
3583	+
3584	+	/**
3585	+	* delayedExecutor returns an executor that delays submission
3586	+	*/
3587	+	public void testDelayedExecutor() {
3588	+	testInParallel(() -> testDelayedExecutor(null, null),
3589	+	() -> testDelayedExecutor(null, 1),
3590	+	() -> testDelayedExecutor(new ThreadExecutor(), 1),
3591	+	() -> testDelayedExecutor(new ThreadExecutor(), 1));
3592	+	}
3593	+
3594	+	public void testDelayedExecutor(Executor executor, Integer v) throws Exception {
3595	+	long timeoutMillis = timeoutMillis();
3596	+	// Use an "unreasonably long" long timeout to catch lingering threads
3597	+	long longTimeoutMillis = 1000 * 60 * 60 * 24;
3598	+	final Executor delayer, longDelayer;
3599	+	if (executor == null) {
3600	+	delayer = CompletableFuture.delayedExecutor(timeoutMillis, MILLISECONDS);
3601	+	longDelayer = CompletableFuture.delayedExecutor(longTimeoutMillis, MILLISECONDS);
3602	+	} else {
3603	+	delayer = CompletableFuture.delayedExecutor(timeoutMillis, MILLISECONDS, executor);
3604	+	longDelayer = CompletableFuture.delayedExecutor(longTimeoutMillis, MILLISECONDS, executor);
3605	+	}
3606	+	long startTime = System.nanoTime();
3607	+	CompletableFuture<Integer> f =
3608	+	CompletableFuture.supplyAsync(() -> v, delayer);
3609	+	CompletableFuture<Integer> g =
3610	+	CompletableFuture.supplyAsync(() -> v, longDelayer);
3611	+
3612	+	assertNull(g.getNow(null));
3613	+
3614	+	assertSame(v, f.get(LONG_DELAY_MS, MILLISECONDS));
3615	+	long millisElapsed = millisElapsedSince(startTime);
3616	+	assertTrue(millisElapsed >= timeoutMillis);
3617	+	assertTrue(millisElapsed < LONG_DELAY_MS / 2);
3618	+
3619	+	checkCompletedNormally(f, v);
3620	+
3621	+	checkIncomplete(g);
3622	+	assertTrue(g.cancel(true));
3623	+	}
3624	+
3625		//--- tests of implementation details; not part of official tck ---
3626
3627		Object resultOf(CompletableFuture<?> f) {
#	Line 3305 | Line 3656 | public class CompletableFutureTest exten
3656		funs.add((y) -> m.thenAcceptBoth(y, v42, new SubtractAction(m)));
3657		funs.add((y) -> m.thenCombine(y, v42, new SubtractFunction(m)));
3658
3659	<	funs.add((y) -> m.whenComplete(y, (Integer x, Throwable t) -> {}));
3659	>	funs.add((y) -> m.whenComplete(y, (Integer r, Throwable t) -> {}));
3660
3661		funs.add((y) -> m.thenCompose(y, new CompletableFutureInc(m)));
3662
#	Line 3361 | Line 3712 | public class CompletableFutureTest exten
3712		}
3713		}}
3714
3715	+	/**
3716	+	* Minimal completion stages throw UOE for all non-CompletionStage methods
3717	+	*/
3718	+	public void testMinimalCompletionStage_minimality() {
3719	+	if (!testImplementationDetails) return;
3720	+	Function<Method, String> toSignature =
3721	+	(method) -> method.getName() + Arrays.toString(method.getParameterTypes());
3722	+	Predicate<Method> isNotStatic =
3723	+	(method) -> (method.getModifiers() & Modifier.STATIC) == 0;
3724	+	List<Method> minimalMethods =
3725	+	Stream.of(Object.class, CompletionStage.class)
3726	+	.flatMap((klazz) -> Stream.of(klazz.getMethods()))
3727	+	.filter(isNotStatic)
3728	+	.collect(Collectors.toList());
3729	+	// Methods from CompletableFuture permitted NOT to throw UOE
3730	+	String[] signatureWhitelist = {
3731	+	"newIncompleteFuture[]",
3732	+	"defaultExecutor[]",
3733	+	"minimalCompletionStage[]",
3734	+	"copy[]",
3735	+	};
3736	+	Set<String> permittedMethodSignatures =
3737	+	Stream.concat(minimalMethods.stream().map(toSignature),
3738	+	Stream.of(signatureWhitelist))
3739	+	.collect(Collectors.toSet());
3740	+	List<Method> allMethods = Stream.of(CompletableFuture.class.getMethods())
3741	+	.filter(isNotStatic)
3742	+	.filter((method) -> !permittedMethodSignatures.contains(toSignature.apply(method)))
3743	+	.collect(Collectors.toList());
3744	+
3745	+	CompletionStage<Integer> minimalStage =
3746	+	new CompletableFuture<Integer>().minimalCompletionStage();
3747	+
3748	+	List<Method> bugs = new ArrayList<>();
3749	+	for (Method method : allMethods) {
3750	+	Class<?>[] parameterTypes = method.getParameterTypes();
3751	+	Object[] args = new Object[parameterTypes.length];
3752	+	// Manufacture boxed primitives for primitive params
3753	+	for (int i = 0; i < args.length; i++) {
3754	+	Class<?> type = parameterTypes[i];
3755	+	if (parameterTypes[i] == boolean.class)
3756	+	args[i] = false;
3757	+	else if (parameterTypes[i] == int.class)
3758	+	args[i] = 0;
3759	+	else if (parameterTypes[i] == long.class)
3760	+	args[i] = 0L;
3761	+	}
3762	+	try {
3763	+	method.invoke(minimalStage, args);
3764	+	bugs.add(method);
3765	+	}
3766	+	catch (java.lang.reflect.InvocationTargetException expected) {
3767	+	if (! (expected.getCause() instanceof UnsupportedOperationException)) {
3768	+	bugs.add(method);
3769	+	// expected.getCause().printStackTrace();
3770	+	}
3771	+	}
3772	+	catch (ReflectiveOperationException bad) { throw new Error(bad); }
3773	+	}
3774	+	if (!bugs.isEmpty())
3775	+	throw new Error("Methods did not throw UOE: " + bugs.toString());
3776	+	}
3777	+
3778	+	static class Monad {
3779	+	static class ZeroException extends RuntimeException {
3780	+	public ZeroException() { super("monadic zero"); }
3781	+	}
3782	+	// "return", "unit"
3783	+	static <T> CompletableFuture<T> unit(T value) {
3784	+	return completedFuture(value);
3785	+	}
3786	+	// monadic zero ?
3787	+	static <T> CompletableFuture<T> zero() {
3788	+	return failedFuture(new ZeroException());
3789	+	}
3790	+	// >=>
3791	+	static <T,U,V> Function<T, CompletableFuture<V>> compose
3792	+	(Function<T, CompletableFuture<U>> f,
3793	+	Function<U, CompletableFuture<V>> g) {
3794	+	return (x) -> f.apply(x).thenCompose(g);
3795	+	}
3796	+
3797	+	static void assertZero(CompletableFuture<?> f) {
3798	+	try {
3799	+	f.getNow(null);
3800	+	throw new AssertionFailedError("should throw");
3801	+	} catch (CompletionException success) {
3802	+	assertTrue(success.getCause() instanceof ZeroException);
3803	+	}
3804	+	}
3805	+
3806	+	static <T> void assertFutureEquals(CompletableFuture<T> f,
3807	+	CompletableFuture<T> g) {
3808	+	T fval = null, gval = null;
3809	+	Throwable fex = null, gex = null;
3810	+
3811	+	try { fval = f.get(); }
3812	+	catch (ExecutionException ex) { fex = ex.getCause(); }
3813	+	catch (Throwable ex) { fex = ex; }
3814	+
3815	+	try { gval = g.get(); }
3816	+	catch (ExecutionException ex) { gex = ex.getCause(); }
3817	+	catch (Throwable ex) { gex = ex; }
3818	+
3819	+	if (fex != null || gex != null)
3820	+	assertSame(fex.getClass(), gex.getClass());
3821	+	else
3822	+	assertEquals(fval, gval);
3823	+	}
3824	+
3825	+	static class PlusFuture<T> extends CompletableFuture<T> {
3826	+	AtomicReference<Throwable> firstFailure = new AtomicReference<>(null);
3827	+	}
3828	+
3829	+	// Monadic "plus"
3830	+	static <T> CompletableFuture<T> plus(CompletableFuture<? extends T> f,
3831	+	CompletableFuture<? extends T> g) {
3832	+	PlusFuture<T> plus = new PlusFuture<T>();
3833	+	BiConsumer<T, Throwable> action = (T result, Throwable ex) -> {
3834	+	if (ex == null) {
3835	+	if (plus.complete(result))
3836	+	if (plus.firstFailure.get() != null)
3837	+	plus.firstFailure.set(null);
3838	+	}
3839	+	else if (plus.firstFailure.compareAndSet(null, ex)) {
3840	+	if (plus.isDone())
3841	+	plus.firstFailure.set(null);
3842	+	}
3843	+	else {
3844	+	// first failure has precedence
3845	+	Throwable first = plus.firstFailure.getAndSet(null);
3846	+
3847	+	// may fail with "Self-suppression not permitted"
3848	+	try { first.addSuppressed(ex); }
3849	+	catch (Exception ignored) {}
3850	+
3851	+	plus.completeExceptionally(first);
3852	+	}
3853	+	};
3854	+	f.whenComplete(action);
3855	+	g.whenComplete(action);
3856	+	return plus;
3857	+	}
3858	+	}
3859	+
3860	+	/**
3861	+	* CompletableFuture is an additive monad - sort of.
3862	+	* https://en.wikipedia.org/wiki/Monad_(functional_programming)#Additive_monads
3863	+	*/
3864	+	public void testAdditiveMonad() throws Throwable {
3865	+	Function<Long, CompletableFuture<Long>> unit = Monad::unit;
3866	+	CompletableFuture<Long> zero = Monad.zero();
3867	+
3868	+	// Some mutually non-commutative functions
3869	+	Function<Long, CompletableFuture<Long>> triple
3870	+	= (x) -> Monad.unit(3 * x);
3871	+	Function<Long, CompletableFuture<Long>> inc
3872	+	= (x) -> Monad.unit(x + 1);
3873	+
3874	+	// unit is a right identity: m >>= unit === m
3875	+	Monad.assertFutureEquals(inc.apply(5L).thenCompose(unit),
3876	+	inc.apply(5L));
3877	+	// unit is a left identity: (unit x) >>= f === f x
3878	+	Monad.assertFutureEquals(unit.apply(5L).thenCompose(inc),
3879	+	inc.apply(5L));
3880	+
3881	+	// associativity: (m >>= f) >>= g === m >>= ( \x -> (f x >>= g) )
3882	+	Monad.assertFutureEquals(
3883	+	unit.apply(5L).thenCompose(inc).thenCompose(triple),
3884	+	unit.apply(5L).thenCompose((x) -> inc.apply(x).thenCompose(triple)));
3885	+
3886	+	// The case for CompletableFuture as an additive monad is weaker...
3887	+
3888	+	// zero is a monadic zero
3889	+	Monad.assertZero(zero);
3890	+
3891	+	// left zero: zero >>= f === zero
3892	+	Monad.assertZero(zero.thenCompose(inc));
3893	+	// right zero: f >>= (\x -> zero) === zero
3894	+	Monad.assertZero(inc.apply(5L).thenCompose((x) -> zero));
3895	+
3896	+	// f plus zero === f
3897	+	Monad.assertFutureEquals(Monad.unit(5L),
3898	+	Monad.plus(Monad.unit(5L), zero));
3899	+	// zero plus f === f
3900	+	Monad.assertFutureEquals(Monad.unit(5L),
3901	+	Monad.plus(zero, Monad.unit(5L)));
3902	+	// zero plus zero === zero
3903	+	Monad.assertZero(Monad.plus(zero, zero));
3904	+	{
3905	+	CompletableFuture<Long> f = Monad.plus(Monad.unit(5L),
3906	+	Monad.unit(8L));
3907	+	// non-determinism
3908	+	assertTrue(f.get() == 5L || f.get() == 8L);
3909	+	}
3910	+
3911	+	CompletableFuture<Long> godot = new CompletableFuture<>();
3912	+	// f plus godot === f (doesn't wait for godot)
3913	+	Monad.assertFutureEquals(Monad.unit(5L),
3914	+	Monad.plus(Monad.unit(5L), godot));
3915	+	// godot plus f === f (doesn't wait for godot)
3916	+	Monad.assertFutureEquals(Monad.unit(5L),
3917	+	Monad.plus(godot, Monad.unit(5L)));
3918	+	}
3919	+
3920	+	//     static <U> U join(CompletionStage<U> stage) {
3921	+	//         CompletableFuture<U> f = new CompletableFuture<>();
3922	+	//         stage.whenComplete((v, ex) -> {
3923	+	//             if (ex != null) f.completeExceptionally(ex); else f.complete(v);
3924	+	//         });
3925	+	//         return f.join();
3926	+	//     }
3927	+
3928	+	//     static <U> boolean isDone(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.isDone();
3934	+	//     }
3935	+
3936	+	//     static <U> U join2(CompletionStage<U> stage) {
3937	+	//         return stage.toCompletableFuture().copy().join();
3938	+	//     }
3939	+
3940	+	//     static <U> boolean isDone2(CompletionStage<U> stage) {
3941	+	//         return stage.toCompletableFuture().copy().isDone();
3942	+	//     }
3943	+
3944		}

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