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Comparing jsr166/src/test/tck/CompletableFutureTest.java (file contents):
Revision 1.127 by jsr166, Sun Oct 25 02:58:25 2015 UTC vs.
Revision 1.138 by jsr166, Sun Nov 15 23:31:51 2015 UTC

# Line 7 | Line 7
7  
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;
# Line 39 | Line 41 | 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  
# Line 873 | 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 })
885      {
# Line 891 | 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 908 | 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 935 | 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 962 | 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 979 | 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 990 | 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 1007 | 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())
1023      {
# Line 1021 | 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 1032 | Line 1040 | public class CompletableFutureTest exten
1040  
1041          checkCompletedWithWrappedException(g, ex1);
1042          checkCompletedExceptionally(f, ex1);
1043 +        assertEquals(1, ex1.getSuppressed().length);
1044 +        assertSame(ex2, ex1.getSuppressed()[0]);
1045          assertEquals(1, a.get());
1046      }}
1047  
# Line 1049 | Line 1059 | public class CompletableFutureTest exten
1059          if (!createIncomplete) assertTrue(f.complete(v1));
1060          final CompletableFuture<Integer> g = m.handle
1061              (f,
1062 <             (Integer x, Throwable t) -> {
1062 >             (Integer result, Throwable t) -> {
1063                  m.checkExecutionMode();
1064 <                threadAssertSame(x, v1);
1064 >                threadAssertSame(result, v1);
1065                  threadAssertNull(t);
1066                  a.getAndIncrement();
1067                  return inc(v1);
# Line 1078 | Line 1088 | public class CompletableFutureTest exten
1088          if (!createIncomplete) f.completeExceptionally(ex);
1089          final CompletableFuture<Integer> g = m.handle
1090              (f,
1091 <             (Integer x, Throwable t) -> {
1091 >             (Integer result, Throwable t) -> {
1092                  m.checkExecutionMode();
1093 <                threadAssertNull(x);
1093 >                threadAssertNull(result);
1094                  threadAssertSame(t, ex);
1095                  a.getAndIncrement();
1096                  return v1;
# Line 1107 | Line 1117 | public class CompletableFutureTest exten
1117          if (!createIncomplete) assertTrue(f.cancel(mayInterruptIfRunning));
1118          final CompletableFuture<Integer> g = m.handle
1119              (f,
1120 <             (Integer x, Throwable t) -> {
1120 >             (Integer result, Throwable t) -> {
1121                  m.checkExecutionMode();
1122 <                threadAssertNull(x);
1122 >                threadAssertNull(result);
1123                  threadAssertTrue(t instanceof CancellationException);
1124                  a.getAndIncrement();
1125                  return v1;
# Line 1122 | Line 1132 | public class CompletableFutureTest exten
1132      }}
1133  
1134      /**
1135 <     * handle result completes exceptionally if action does
1135 >     * If a "handle action" throws an exception when triggered by
1136 >     * a normal completion, it completes exceptionally
1137       */
1138 <    public void testHandle_sourceFailedActionFailed() {
1138 >    public void testHandle_sourceCompletedNormallyActionFailed() {
1139          for (ExecutionMode m : ExecutionMode.values())
1140          for (boolean createIncomplete : new boolean[] { true, false })
1141 +        for (Integer v1 : new Integer[] { 1, null })
1142      {
1143          final CompletableFuture<Integer> f = new CompletableFuture<>();
1144          final AtomicInteger a = new AtomicInteger(0);
1145 <        final CFException ex1 = new CFException();
1146 <        final CFException ex2 = new CFException();
1135 <        if (!createIncomplete) f.completeExceptionally(ex1);
1145 >        final CFException ex = new CFException();
1146 >        if (!createIncomplete) assertTrue(f.complete(v1));
1147          final CompletableFuture<Integer> g = m.handle
1148              (f,
1149 <             (Integer x, Throwable t) -> {
1149 >             (Integer result, Throwable t) -> {
1150                  m.checkExecutionMode();
1151 <                threadAssertNull(x);
1152 <                threadAssertSame(ex1, t);
1151 >                threadAssertSame(result, v1);
1152 >                threadAssertNull(t);
1153                  a.getAndIncrement();
1154 <                throw ex2;
1154 >                throw ex;
1155              });
1156 <        if (createIncomplete) f.completeExceptionally(ex1);
1156 >        if (createIncomplete) assertTrue(f.complete(v1));
1157  
1158 <        checkCompletedWithWrappedException(g, ex2);
1159 <        checkCompletedExceptionally(f, ex1);
1158 >        checkCompletedWithWrappedException(g, ex);
1159 >        checkCompletedNormally(f, v1);
1160          assertEquals(1, a.get());
1161      }}
1162  
1163 <    public void testHandle_sourceCompletedNormallyActionFailed() {
1164 <        for (ExecutionMode m : ExecutionMode.values())
1163 >    /**
1164 >     * If a "handle action" throws an exception when triggered by
1165 >     * a source completion that also throws an exception, the action
1166 >     * exception takes precedence (unlike whenComplete)
1167 >     */
1168 >    public void testHandle_sourceFailedActionFailed() {
1169          for (boolean createIncomplete : new boolean[] { true, false })
1170 <        for (Integer v1 : new Integer[] { 1, null })
1170 >        for (ExecutionMode m : ExecutionMode.values())
1171      {
1157        final CompletableFuture<Integer> f = new CompletableFuture<>();
1172          final AtomicInteger a = new AtomicInteger(0);
1173 <        final CFException ex = new CFException();
1174 <        if (!createIncomplete) assertTrue(f.complete(v1));
1173 >        final CFException ex1 = new CFException();
1174 >        final CFException ex2 = new CFException();
1175 >        final CompletableFuture<Integer> f = new CompletableFuture<>();
1176 >
1177 >        if (!createIncomplete) f.completeExceptionally(ex1);
1178          final CompletableFuture<Integer> g = m.handle
1179              (f,
1180 <             (Integer x, Throwable t) -> {
1180 >             (Integer result, Throwable t) -> {
1181                  m.checkExecutionMode();
1182 <                threadAssertSame(x, v1);
1183 <                threadAssertNull(t);
1182 >                threadAssertNull(result);
1183 >                threadAssertSame(ex1, t);
1184                  a.getAndIncrement();
1185 <                throw ex;
1185 >                throw ex2;
1186              });
1187 <        if (createIncomplete) assertTrue(f.complete(v1));
1187 >        if (createIncomplete) f.completeExceptionally(ex1);
1188  
1189 <        checkCompletedWithWrappedException(g, ex);
1190 <        checkCompletedNormally(f, v1);
1189 >        checkCompletedWithWrappedException(g, ex2);
1190 >        checkCompletedExceptionally(f, ex1);
1191          assertEquals(1, a.get());
1192      }}
1193  
# Line 3641 | Line 3658 | public class CompletableFutureTest exten
3658          funs.add((y) -> m.thenAcceptBoth(y, v42, new SubtractAction(m)));
3659          funs.add((y) -> m.thenCombine(y, v42, new SubtractFunction(m)));
3660  
3661 <        funs.add((y) -> m.whenComplete(y, (Integer x, Throwable t) -> {}));
3661 >        funs.add((y) -> m.whenComplete(y, (Integer r, Throwable t) -> {}));
3662  
3663          funs.add((y) -> m.thenCompose(y, new CompletableFutureInc(m)));
3664  
# Line 3760 | Line 3777 | public class CompletableFutureTest exten
3777              throw new Error("Methods did not throw UOE: " + bugs.toString());
3778      }
3779  
3780 +    static class Monad {
3781 +        static class ZeroException extends RuntimeException {
3782 +            public ZeroException() { super("monadic zero"); }
3783 +        }
3784 +        // "return", "unit"
3785 +        static <T> CompletableFuture<T> unit(T value) {
3786 +            return completedFuture(value);
3787 +        }
3788 +        // monadic zero ?
3789 +        static <T> CompletableFuture<T> zero() {
3790 +            return failedFuture(new ZeroException());
3791 +        }
3792 +        // >=>
3793 +        static <T,U,V> Function<T, CompletableFuture<V>> compose
3794 +            (Function<T, CompletableFuture<U>> f,
3795 +             Function<U, CompletableFuture<V>> g) {
3796 +            return (x) -> f.apply(x).thenCompose(g);
3797 +        }
3798 +
3799 +        static void assertZero(CompletableFuture<?> f) {
3800 +            try {
3801 +                f.getNow(null);
3802 +                throw new AssertionFailedError("should throw");
3803 +            } catch (CompletionException success) {
3804 +                assertTrue(success.getCause() instanceof ZeroException);
3805 +            }
3806 +        }
3807 +
3808 +        static <T> void assertFutureEquals(CompletableFuture<T> f,
3809 +                                           CompletableFuture<T> g) {
3810 +            T fval = null, gval = null;
3811 +            Throwable fex = null, gex = null;
3812 +
3813 +            try { fval = f.get(); }
3814 +            catch (ExecutionException ex) { fex = ex.getCause(); }
3815 +            catch (Throwable ex) { fex = ex; }
3816 +
3817 +            try { gval = g.get(); }
3818 +            catch (ExecutionException ex) { gex = ex.getCause(); }
3819 +            catch (Throwable ex) { gex = ex; }
3820 +
3821 +            if (fex != null || gex != null)
3822 +                assertSame(fex.getClass(), gex.getClass());
3823 +            else
3824 +                assertEquals(fval, gval);
3825 +        }
3826 +
3827 +        static class PlusFuture<T> extends CompletableFuture<T> {
3828 +            AtomicReference<Throwable> firstFailure = new AtomicReference<>(null);
3829 +        }
3830 +
3831 +        /** Implements "monadic plus". */
3832 +        static <T> CompletableFuture<T> plus(CompletableFuture<? extends T> f,
3833 +                                             CompletableFuture<? extends T> g) {
3834 +            PlusFuture<T> plus = new PlusFuture<T>();
3835 +            BiConsumer<T, Throwable> action = (T result, Throwable ex) -> {
3836 +                try {
3837 +                    if (ex == null) {
3838 +                        if (plus.complete(result))
3839 +                            if (plus.firstFailure.get() != null)
3840 +                                plus.firstFailure.set(null);
3841 +                    }
3842 +                    else if (plus.firstFailure.compareAndSet(null, ex)) {
3843 +                        if (plus.isDone())
3844 +                            plus.firstFailure.set(null);
3845 +                    }
3846 +                    else {
3847 +                        // first failure has precedence
3848 +                        Throwable first = plus.firstFailure.getAndSet(null);
3849 +
3850 +                        // may fail with "Self-suppression not permitted"
3851 +                        try { first.addSuppressed(ex); }
3852 +                        catch (Exception ignored) {}
3853 +
3854 +                        plus.completeExceptionally(first);
3855 +                    }
3856 +                } catch (Throwable unexpected) {
3857 +                    plus.completeExceptionally(unexpected);
3858 +                }
3859 +            };
3860 +            f.whenComplete(action);
3861 +            g.whenComplete(action);
3862 +            return plus;
3863 +        }
3864 +    }
3865 +
3866 +    /**
3867 +     * CompletableFuture is an additive monad - sort of.
3868 +     * https://en.wikipedia.org/wiki/Monad_(functional_programming)#Additive_monads
3869 +     */
3870 +    public void testAdditiveMonad() throws Throwable {
3871 +        Function<Long, CompletableFuture<Long>> unit = Monad::unit;
3872 +        CompletableFuture<Long> zero = Monad.zero();
3873 +
3874 +        // Some mutually non-commutative functions
3875 +        Function<Long, CompletableFuture<Long>> triple
3876 +            = (x) -> Monad.unit(3 * x);
3877 +        Function<Long, CompletableFuture<Long>> inc
3878 +            = (x) -> Monad.unit(x + 1);
3879 +
3880 +        // unit is a right identity: m >>= unit === m
3881 +        Monad.assertFutureEquals(inc.apply(5L).thenCompose(unit),
3882 +                                 inc.apply(5L));
3883 +        // unit is a left identity: (unit x) >>= f === f x
3884 +        Monad.assertFutureEquals(unit.apply(5L).thenCompose(inc),
3885 +                                 inc.apply(5L));
3886 +
3887 +        // associativity: (m >>= f) >>= g === m >>= ( \x -> (f x >>= g) )
3888 +        Monad.assertFutureEquals(
3889 +            unit.apply(5L).thenCompose(inc).thenCompose(triple),
3890 +            unit.apply(5L).thenCompose((x) -> inc.apply(x).thenCompose(triple)));
3891 +
3892 +        // The case for CompletableFuture as an additive monad is weaker...
3893 +
3894 +        // zero is a monadic zero
3895 +        Monad.assertZero(zero);
3896 +
3897 +        // left zero: zero >>= f === zero
3898 +        Monad.assertZero(zero.thenCompose(inc));
3899 +        // right zero: f >>= (\x -> zero) === zero
3900 +        Monad.assertZero(inc.apply(5L).thenCompose((x) -> zero));
3901 +
3902 +        // f plus zero === f
3903 +        Monad.assertFutureEquals(Monad.unit(5L),
3904 +                                 Monad.plus(Monad.unit(5L), zero));
3905 +        // zero plus f === f
3906 +        Monad.assertFutureEquals(Monad.unit(5L),
3907 +                                 Monad.plus(zero, Monad.unit(5L)));
3908 +        // zero plus zero === zero
3909 +        Monad.assertZero(Monad.plus(zero, zero));
3910 +        {
3911 +            CompletableFuture<Long> f = Monad.plus(Monad.unit(5L),
3912 +                                                   Monad.unit(8L));
3913 +            // non-determinism
3914 +            assertTrue(f.get() == 5L || f.get() == 8L);
3915 +        }
3916 +
3917 +        CompletableFuture<Long> godot = new CompletableFuture<>();
3918 +        // f plus godot === f (doesn't wait for godot)
3919 +        Monad.assertFutureEquals(Monad.unit(5L),
3920 +                                 Monad.plus(Monad.unit(5L), godot));
3921 +        // godot plus f === f (doesn't wait for godot)
3922 +        Monad.assertFutureEquals(Monad.unit(5L),
3923 +                                 Monad.plus(godot, Monad.unit(5L)));
3924 +    }
3925 +
3926   //     static <U> U join(CompletionStage<U> stage) {
3927   //         CompletableFuture<U> f = new CompletableFuture<>();
3928   //         stage.whenComplete((v, ex) -> {

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