Examples with Collectors.toList java8.util.stream.Collectors.toList used on opensource projects

Example 1 with Collectors.toList

use of java8.util.stream.Collectors.toList in project streamsupport by stefan-zobel.

the class CompletableFutureTest method testMinimalCompletionStage_minimality.

/**
 * Minimal completion stages throw UOE for most non-CompletionStage methods
 */
public void testMinimalCompletionStage_minimality() {
    if (!testImplementationDetails)
        return;
    Function<Method, String> toSignature = method -> method.getName() + Arrays.toString(method.getParameterTypes());
    Predicate<Method> isNotStatic = method -> (method.getModifiers() & Modifier.STATIC) == 0;
    List<Method> minimalMethods = RefStreams.of(Object.class, CompletionStage.class).flatMap(klazz -> RefStreams.of(klazz.getMethods())).filter(isNotStatic).collect(Collectors.toList());
    // Methods from CompletableFuture permitted NOT to throw UOE
    String[] signatureWhitelist = { "newIncompleteFuture[]", "defaultExecutor[]", "minimalCompletionStage[]", "copy[]" };
    Set<String> permittedMethodSignatures = RefStreams.concat(StreamSupport.stream(minimalMethods).map(toSignature), RefStreams.of(signatureWhitelist)).collect(Collectors.toSet());
    List<Method> allMethods = RefStreams.of(CompletableFuture.class.getMethods()).filter(isNotStatic).filter(method -> !permittedMethodSignatures.contains(toSignature.apply(method))).collect(Collectors.toList());
    List<CompletionStage<Integer>> stages = new ArrayList<CompletionStage<Integer>>();
    CompletionStage<Integer> min = new CompletableFuture<Integer>().minimalCompletionStage();
    stages.add(min);
    stages.add(min.thenApply(x -> x));
    stages.add(CompletableFuture.completedStage(1));
    stages.add(CompletableFuture.failedStage(new CFException()));
    List<Method> bugs = new ArrayList<>();
    for (Method method : allMethods) {
        Class<?>[] parameterTypes = method.getParameterTypes();
        Object[] args = new Object[parameterTypes.length];
        // Manufacture boxed primitives for primitive params
        for (int i = 0; i < args.length; i++) {
            Class<?> type = parameterTypes[i];
            if (type == boolean.class)
                args[i] = false;
            else if (type == int.class)
                args[i] = 0;
            else if (type == long.class)
                args[i] = 0L;
        }
        for (CompletionStage<Integer> stage : stages) {
            try {
                method.invoke(stage, args);
                bugs.add(method);
            } catch (java.lang.reflect.InvocationTargetException expected) {
                if (!(expected.getCause() instanceof UnsupportedOperationException)) {
                    bugs.add(method);
                // expected.getCause().printStackTrace();
                }
            } catch (Exception bad) {
                throw new Error(bad);
            }
        }
    }
    if (!bugs.isEmpty())
        throw new Error("Methods did not throw UOE: " + bugs);
}

Example 2 with Collectors.toList

use of java8.util.stream.Collectors.toList in project streamsupport by stefan-zobel.

the class Collection8Test method testDetectRaces.

/**
 * Motley crew of threads concurrently randomly hammer the collection.
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
@Test(dataProvider = "Source")
public void testDetectRaces(String description, Supplier<CollectionImplementation> sci) throws Throwable {
    CollectionImplementation impl = sci.get();
    if (!impl.isConcurrent())
        return;
    if (HAS_JAVA8_SPLITERATOR_BUG && LinkedBlockingDeque.class.equals(impl.klazz())) {
        // https://bugs.openjdk.java.net/browse/JDK-8169739
        return;
    }
    if (CopyOnWriteArraySet.class.equals(impl.klazz())) {
        return;
    }
    final ThreadLocalRandom rnd = ThreadLocalRandom.current();
    final Collection c = impl.emptyCollection();
    final long testDurationMillis = expensiveTests ? LONG_DELAY_MS : timeoutMillis();
    final AtomicBoolean done = new AtomicBoolean(false);
    final Object one = impl.makeElement(1);
    final Object two = impl.makeElement(2);
    final Consumer checkSanity = x -> assertTrue(x == one || x == two);
    final Consumer<Object[]> checkArraySanity = array -> {
        // assertTrue(array.length <= 2); // duplicates are permitted
        for (Object x : array) assertTrue(x == one || x == two);
    };
    final Object[] emptyArray = (Object[]) java.lang.reflect.Array.newInstance(one.getClass(), 0);
    final List<Future<?>> futures;
    // register this thread
    final Phaser threadsStarted = new Phaser(1);
    final Runnable[] frobbers = { () -> Iterables.forEach(c, checkSanity), () -> StreamSupport.stream(c).forEach(checkSanity), () -> StreamSupport.parallelStream(c).forEach(checkSanity), () -> Spliterators.spliterator(c).trySplit(), () -> {
        Spliterator<?> s = Spliterators.spliterator(c);
        s.tryAdvance(checkSanity);
        s.trySplit();
    }, () -> {
        Spliterator<?> s = Spliterators.spliterator(c);
        do {
        } while (s.tryAdvance(checkSanity));
    }, () -> {
        for (Object x : c) checkSanity.accept(x);
    }, () -> checkArraySanity.accept(c.toArray()), () -> checkArraySanity.accept(c.toArray(emptyArray)), () -> {
        Object[] a = new Object[5];
        Object three = impl.makeElement(3);
        Arrays.fill(a, 0, a.length, three);
        Object[] x = c.toArray(a);
        if (x == a)
            for (int i = 0; i < a.length && a[i] != null; i++) checkSanity.accept(a[i]);
        else
            // A careful reading of the spec does not support:
            // for (i++; i < a.length; i++) assertSame(three, a[i]);
            checkArraySanity.accept(x);
    }, adderRemover(c, one), adderRemover(c, two) };
    final List<Runnable> tasks = J8Arrays.stream(frobbers).filter(// random subset
    task -> rnd.nextBoolean()).map(task -> (Runnable) () -> {
        threadsStarted.arriveAndAwaitAdvance();
        while (!done.get()) task.run();
    }).collect(Collectors.<Runnable>toList());
    final ExecutorService pool = Executors.newCachedThreadPool();
    PoolCleaner cleaner = null;
    try {
        cleaner = cleaner(pool, done);
        threadsStarted.bulkRegister(tasks.size());
        futures = StreamSupport.stream(tasks).map(pool::submit).collect(Collectors.toList());
        threadsStarted.arriveAndDeregister();
        Thread.sleep(testDurationMillis);
    } finally {
        if (cleaner != null) {
            cleaner.close();
        }
    }
    for (Future<?> future : futures) assertNull(future.get(0L, MILLISECONDS));
}