Java Code Examples for java.util.stream.Stream

@Override
public Object resolveParameter(final ParameterContext parameterContext, final ExtensionContext extensionContext)
        throws ParameterResolutionException {
    if (super.supports(parameterContext.getParameter().getType())) {
        return super.findInstance(extensionContext, parameterContext.getParameter().getType());
    }
    final DependenciesTxtBuilder builder = new DependenciesTxtBuilder();
    final String[] deps = parameterContext.getParameter().getAnnotation(Instance.class).value();
    Stream.of(deps).forEach(builder::withDependency);
    return manager
            .get()
            .builder(extensionContext.getRequiredTestClass().getName() + "."
                    + extensionContext.getRequiredTestMethod().getName() + "#" + manager.get().findAll().size(),
                    create(builder.build()).getAbsolutePath())
            .create();
}
 

@Before
public void setUp() throws MalformedURLException {
    LogProvider.injectDebugLogger(System.out::println);

    final String testClassPath = "src/test/jaxrs-test";

    // invoke compilation for jaxrs-test classes
    final JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
    final StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
    final List<JavaFileObject> compilationUnits = findClassFiles(testClassPath, fileManager);

    final JavaCompiler.CompilationTask compilationTask = compiler.getTask(null, null, null, singletonList("-g"), null, compilationUnits);
    assertTrue("Could not compile test project", compilationTask.call());

    path = Paths.get(testClassPath).toAbsolutePath();

    final Set<Path> classPaths = Stream.of(System.getProperty("java.class.path").split(File.pathSeparator))
            .map(Paths::get)
            .collect(Collectors.toSet());

    classPaths.add(path);
    classUnderTest = new ProjectAnalyzer(classPaths);
}
 

@Test
public void should_summarize_a_non_empty_stream_with_correct_substreams_content() {
    // Given
    Stream<String> strings = Stream.of("2", "4", "2", "4", "2", "4", "2");
    int groupingFactor = 2;
    LongSummaryStatistics stats = new LongSummaryStatistics();
    stats.accept(2L);
    stats.accept(4L);

    // When
    Stream<LongSummaryStatistics> summarizedStream = StreamsUtils.shiftingWindowSummarizingLong(strings, groupingFactor, Long::parseLong);
    List<LongSummaryStatistics> result = summarizedStream.collect(toList());

    // When
    assertThat(result.size()).isEqualTo(6);
    assertThat(result.get(0).toString()).isEqualTo(stats.toString());
    assertThat(result.get(1).toString()).isEqualTo(stats.toString());
    assertThat(result.get(2).toString()).isEqualTo(stats.toString());
    assertThat(result.get(3).toString()).isEqualTo(stats.toString());
    assertThat(result.get(4).toString()).isEqualTo(stats.toString());
    assertThat(result.get(5).toString()).isEqualTo(stats.toString());
}
 

@Test
public void testSplitIterator() {
    PageFetcherCurrentAndTotalPagesSplitIterator<Integer> integerPageFetcherSplitIterator = new PageFetcherCurrentAndTotalPagesSplitIterator<>(pageToFetch -> {
        // return fake paginated result

        int startIdx = pageToFetch * 10;
        int endIdx = pageToFetch == 5 ? (pageToFetch + 1) * 10 - 5 : (pageToFetch + 1) * 10;

        List<Integer> collect = IntStream.range(startIdx, endIdx).boxed().collect(Collectors.toList());
        ListWithLastPage<Integer> list = new ListWithLastPage<>();
        list.setList(collect);
        list.setLastPage(5);
        return list;
    }, 0);

    Stream<Integer> stream = StreamSupport.stream(integerPageFetcherSplitIterator, false);

    assertEquals(
            IntStream.range(0, 55).boxed().collect(Collectors.toList()),
            stream.collect(Collectors.toList())
    );
}
 

@Test
public void testMultiSourceAndHoleAndMultiSink() throws URISyntaxException {
    // Define some input data.
    final List<String> collection1 = Arrays.asList("This is source 1.", "This is source 1, too.");
    final List<String> collection2 = Arrays.asList("This is source 2.", "This is source 2, too.");
    List<String> collector1 = new LinkedList<>();
    List<String> collector2 = new LinkedList<>();
    final RheemPlan rheemPlan = RheemPlans.multiSourceHoleMultiSink(collection1, collection2, collector1, collector2);


    makeAndRun(rheemPlan, FLINK);

    // Check the results in both sinks.
    List<String> expectedOutcome = Stream.concat(collection1.stream(), collection2.stream())
            .flatMap(string -> Arrays.asList(string.toLowerCase(), string.toUpperCase()).stream())
            .collect(Collectors.toList());
    Collections.sort(expectedOutcome);
    Collections.sort(collector1);
    Collections.sort(collector2);
    Assert.assertEquals(expectedOutcome, collector1);
    Assert.assertEquals(expectedOutcome, collector2);
}
 

@Test
void testInfo() throws IOException {
  Request<InfoRequest> request = new Request<InfoRequest>();
  request.setOp("info");

  InfoRequest params = new InfoRequest();
  params.setBlockHash("00000");
  params.setNum(100);
  params.setTable("t_demo");

  request.setParams(params);
  String content = objectMapper.writeValueAsString(request);
  String result = dbService.process(content);

  MockResponse<InfoResponse> response =
      objectMapper.readValue(result, new TypeReference<MockResponse<InfoResponse>>() {});

  assertEquals(response.getCode(), new Integer(0));
  InfoResponse info = (InfoResponse) response.getResult();

  assertLinesMatch(info.getIndices(),
      Stream.of("field1", "field2", "field3").collect(Collectors.toList()));
}
 

@Test
public void should_accumulate_an_entry_stream_into_the_correct_entry_stream() {
    // Given
    Stream<Map.Entry<Integer, String>> entries =
            Stream.of(
                    new AbstractMap.SimpleEntry<>(1, "1"),
                    new AbstractMap.SimpleEntry<>(2, "2"),
                    new AbstractMap.SimpleEntry<>(3, "3"),
                    new AbstractMap.SimpleEntry<>(4, "4")
            );

    // When
    Stream<Map.Entry<Integer, String>> accumulate = StreamsUtils.accumulateEntries(entries, String::concat);

    // Then
    assertThat(accumulate.collect(toList())).containsExactly(
            new AbstractMap.SimpleEntry<>(1, "1"),
            new AbstractMap.SimpleEntry<>(2, "12"),
            new AbstractMap.SimpleEntry<>(3, "123"),
            new AbstractMap.SimpleEntry<>(4, "1234")
    );
}
 

/**
 * Returns a {@code Stream} of all public getter methods which match {@code predicate} and their return values for the given object.
 * <p>
 * This method uses reflection to find all of the public instance methods which don't take any arguments
 * and return a value.  If they pass the given predicate, then they are called, and the return value is
 * included in a stream of {@code Map.Entry<Method, Object>}.
 * <p>
 * Note that there are some methods which have the signature of a getter, but actually mutate the object
 * being inspected, e.g. {@link java.io.InputStream#read()}.  These will be called unless you manually
 * exclude them using the predicate.
 */
public static Stream<Map.Entry<Method, Object>> getters(Object obj, Predicate<Method> predicate) {
	Class<?> clazz = obj == null ? ObjectIsNull.class : obj.getClass();
	return Arrays.asList(clazz.getMethods()).stream()
			// we only want methods that don't take parameters
			.filter(method -> method.getParameterTypes().length == 0)
			// we only want public methods
			.filter(method -> Modifier.isPublic(method.getModifiers()))
			// we only want instance methods
			.filter(method -> !Modifier.isStatic(method.getModifiers()))
			// we only want methods that don't return void
			.filter(method -> !method.getReturnType().equals(Void.TYPE))
			// we only want methods that pass our predicate
			.filter(predicate)
			// turn it into Map<Method, Result>
			.map(method -> createEntry(method, tryCall(method.getName(), () -> method.invoke(obj))));
}
 

private ClientBuilder createClient(final ExecutorService executor, final Optional<String> keystoreLocation,
        final Optional<String> keystoreType, final String keystorePassword, final Optional<String> truststoreType,
        final List<String> serverHostnames) {
    final ClientBuilder builder = ClientBuilder.newBuilder();
    builder.connectTimeout(connectTimeout, MILLISECONDS);
    builder.readTimeout(readTimeout, MILLISECONDS);
    builder.executorService(executor);
    if (acceptAnyCertificate) {
        builder.hostnameVerifier((host, session) -> true);
        builder.sslContext(createUnsafeSSLContext());
    } else if (keystoreLocation.isPresent()) {
        builder.hostnameVerifier((host, session) -> serverHostnames.contains(host));
        builder.sslContext(createSSLContext(keystoreLocation, keystoreType, keystorePassword, truststoreType));
    }
    providers.map(it -> Stream.of(it.split(",")).map(String::trim).filter(v -> !v.isEmpty()).map(fqn -> {
        try {
            return Thread.currentThread().getContextClassLoader().loadClass(fqn).getConstructor().newInstance();
        } catch (final Exception e) {
            log.warn("Can't add provider " + fqn + ": " + e.getMessage(), e);
            return null;
        }
    }).filter(Objects::nonNull)).ifPresent(it -> it.forEach(builder::register));
    return ClientTracingRegistrar.configure(builder);
}
 

@Test
public void getCaseInstanceWithTwoInvolvedGroups() {
    CaseInstance caseInstance = cmmnRuntimeService.createCaseInstanceBuilder()
            .caseDefinitionKey("oneTaskCase")
            .start();
    cmmnRuntimeService.addGroupIdentityLink(caseInstance.getId(), "testGroup", IdentityLinkType.PARTICIPANT);
    cmmnRuntimeService.addGroupIdentityLink(caseInstance.getId(), "testGroup2", IdentityLinkType.PARTICIPANT);

    assertThat(cmmnHistoryService.createHistoricCaseInstanceQuery().involvedGroups(
            Stream.of("testGroup", "testGroup2", "testGroup3").collect(Collectors.toSet())).count())
            .isEqualTo(1);
    assertThat(cmmnHistoryService.createHistoricCaseInstanceQuery().involvedGroups(
            Stream.of("testGroup", "testGroup2", "testGroup3").collect(Collectors.toSet())).list().get(0).getId()).isEqualTo(caseInstance.getId());
    assertThat(cmmnHistoryService.createHistoricCaseInstanceQuery().involvedGroups(
            Stream.of("testGroup", "testGroup2", "testGroup3").collect(Collectors.toSet())).singleResult().getId()).isEqualTo(caseInstance.getId());
}
 

private static void run(Path configFile, PropertySequence propertySeq, List<String> arguments) {
  //System.out.println("run with jshell " + configFile);
  
  var args =
    Stream.of(
      Stream.of("-R-XX:+EnableValhalla").filter(__ -> System.getProperty("valhalla.enableValhalla") != null),
      Stream.of("-R--add-modules=ALL-SYSTEM"),  // also add incubator modules
      Stream.of("-R--enable-preview"),
      Stream.of("-R-Dpro.exitOnError=false"),
      propertySeq.stream().map(entry -> "-D" + entry.getKey() + '=' + entry.getValue()),
      Stream.of(arguments).filter(a -> !a.isEmpty()).map(a -> "-R-Dpro.arguments=" + String.join(",", a)),
      Stream.of(configFile.toString())
      )
    .flatMap(s -> s)
    .toArray(String[]::new);
  
  int exitCode = JShellWrapper.run(System.in, System.out, System.err, args);
  if (exitCode != 0) {
    System.err.println("error while executing jshell " + String.join(" ", args));
  }
  System.exit(exitCode);
}
 

private static void assertContains(Stream<User> expected, List<User> actual) {
  Iterator<User> expIt = expected.iterator();
  if (!expIt.hasNext()) {
    return;
  }
  User exp = expIt.next();
  for (User act : actual) {
    if (act.equals(exp)) {
      if (!expIt.hasNext()) {
        break;
      }
      exp = expIt.next();
    }
  }
  assertFalse("Not all expected elements are in the actual list. E.g.: " + exp, expIt.hasNext());
}
 

private Set<String> packages(Path dir) {
    try (Stream<Path> stream = Files.find(dir, Integer.MAX_VALUE,
                         ((path, attrs) -> attrs.isRegularFile() &&
                                           path.toString().endsWith(".class")))) {
        return stream.map(path -> toPackageName(dir.relativize(path)))
                     .filter(pkg -> pkg.length() > 0)   // module-info
                     .distinct()
                     .collect(Collectors.toSet());
    } catch (IOException x) {
        throw new UncheckedIOException(x);
    }
}
 

@Test
void multiple_StreamToSetWithDiffTypeMappingDuplicates_ReturnsSetOfMappedValuesWithDuplicates() {
    final Set<CompletableFuture<Integer>> futures = mapValuesToFutures(Stream.of("john", "john"),
        element -> completedFuture(element.length()), toSet());

    assertThat(futures).hasSize(2);
    assertThat(futures).isExactlyInstanceOf(HashSet.class);

    final List<Integer> results = futures.stream()
                                         .map(CompletableFuture::join)
                                         .collect(toList());


    assertThat(results).containsExactly(4, 4);
}
 

@Test
public void should_conform_to_specified_trySplit_behavior() {
    // Given
    Stream<String> strings = Stream.of("a", "d", "c", "b");
    Stream<Map.Entry<String, String>> stream = StreamsUtils.crossProductNaturallyOrdered(strings);
    TryAdvanceCheckingSpliterator<Map.Entry<String, String>> spliterator = new TryAdvanceCheckingSpliterator<>(stream.spliterator());
    Stream<Map.Entry<String, String>> monitoredStream = StreamSupport.stream(spliterator, false);

    // When
    long count = monitoredStream.count();

    // Then
    assertThat(count).isEqualTo(6L);
}
 

@Test
public void whenInitializeUnmodifiableSetWithDoubleBrace_containsElements() {
     Set<String> countries = Stream.of("India", "USSR", "USA")
       .collect(collectingAndThen(toSet(), Collections::unmodifiableSet));

    assertTrue(countries.contains("India"));
}
 

@Override
public <T> Optional<T> findData(MarketDataName<T> name) {
  if (name instanceof CurveName) {
    return Stream.concat(repoCurves.values().stream(), issuerCurves.values().stream())
        .map(df -> df.findData(name))
        .filter(opt -> opt.isPresent())
        .map(opt -> opt.get())
        .findFirst();
  }
  return Optional.empty();
}
 

private Stream<IRI> getSubClassesFor(OWLClass owlClass, boolean direct) {
    if (direct) {
        return owlOntology.axioms(AxiomType.SUBCLASS_OF, Imports.INCLUDED)
                .filter(axiom -> axiom.getSuperClass().equals(owlClass))
                .map(OWLSubClassOfAxiom::getSubClass)
                .filter(subclass -> !subclass.isBottomEntity() && subclass.isOWLClass()
                            && !subclass.asOWLClass().getIRI().equals(owlClass.getIRI()))
                .map(subclass -> SimpleOntologyValues.mobiIRI(subclass.asOWLClass().getIRI()));
    } else {
        return owlReasoner.getSubClasses(owlClass, false).entities()
                .filter(subclass -> !subclass.isBottomEntity() && !subclass.getIRI().equals(owlClass.getIRI()))
                .map(subclass -> SimpleOntologyValues.mobiIRI(subclass.getIRI()));
    }
}
 

@Test(dataProvider = "sizes")
public void testAfterBuilding(int size) {
    Stream.Builder<Integer> sb = Stream.builder();
    IntStream.range(0, size).boxed().forEach(sb);
    sb.build();

    checkISE(() -> sb.accept(1));
    checkISE(() -> sb.add(1));
    checkISE(() -> sb.build());
}
 

private void serializeAssociations( final EntityState entityState,
                                    final Graph graph, URI entityUri,
                                    final Stream<? extends AssociationDescriptor> associations,
                                    final boolean includeNonQueryable
)
{
    ValueFactory values = graph.getValueFactory();

    // Associations
    associations.filter( type -> includeNonQueryable || type.queryable() ).forEach(
        associationType ->
        {
            EntityReference associatedId
                = entityState
                .associationValueOf(
                    associationType
                        .qualifiedName() );
            if( associatedId != null )
            {
                URI assocURI = values
                    .createURI(
                        associationType
                            .qualifiedName()
                            .toURI() );
                URI assocEntityURI
                    = values.createURI(
                    associatedId
                        .toURI() );
                graph.add( entityUri,
                           assocURI,
                           assocEntityURI );
            }
        } );
}
 

@Override
protected IStatus run(IProgressMonitor monitor) {
	List<?> types = getTypes(cUnit);

	types.stream().filter(type -> {
		try {
			return Stream.of(superClasses).anyMatch(
					superClass -> SharedUtils.typeIsAssignableFrom((TypeDeclaration) type, superClass));
		} catch (NullPointerException ex) {
			return false;
		}
	}).forEach(type -> typesWithGivenSuperclass
			.add((IType) ((TypeDeclaration) type).resolveBinding().getJavaElement()));
	return Status.OK_STATUS;
}
 

private Enrolment getDissertationEnrolment() {
    Stream<Enrolment> enrolments = getGroup().getEnrolmentsSet().stream().filter(Enrolment::isDissertation);

    List<Dismissal> dismissalsList = new ArrayList<>();
    getGroup().collectDismissals(dismissalsList);

    Stream<Enrolment> dismissals =
            dismissalsList.stream().flatMap(d -> d.getSourceIEnrolments().stream())
                    .filter(e -> e.isEnrolment() && ((Enrolment) e).isDissertation()).map(ie -> (Enrolment) ie);
    return Stream.concat(enrolments, dismissals).max(Enrolment.COMPARATOR_BY_EXECUTION_PERIOD_AND_ID).orElse(null);
}
 

@Test
public void givenOperationThatThrowsCheckedException_whenExecuteUsingUncheckedFuction_shouldPass() {
    // when
    List<Integer> collect = Stream.of("a", "b", "c").map(Unchecked.function(this::methodThatThrowsChecked)).collect(Collectors.toList());

    // then
    assertEquals(collect, Arrays.asList(1, 1, 1));
}
 

private void schedulePendingMirrors() {
    final ZonedDateTime now = ZonedDateTime.now();
    if (lastExecutionTime == null) {
        lastExecutionTime = now.minus(TICK);
    }

    final ZonedDateTime currentLastExecutionTime = lastExecutionTime;
    lastExecutionTime = now;

    projectManager.list().values().stream()
                  .map(Project::metaRepo)
                  .flatMap(r -> {
                      try {
                          return r.mirrors().stream();
                      } catch (Exception e) {
                          logger.warn("Failed to load the mirror list from: {}", r.parent().name(), e);
                          return Stream.empty();
                      }
                  })
                  .filter(m -> m.nextExecutionTime(currentLastExecutionTime).compareTo(now) < 0)
                  .forEach(m -> {
                      final ListenableFuture<?> future = worker.submit(() -> run(m, true));
                      Futures.addCallback(future, new FutureCallback<Object>() {
                          @Override
                          public void onSuccess(@Nullable Object result) {}

                          @Override
                          public void onFailure(Throwable cause) {
                              logger.warn("Unexpected Git-to-CD mirroring failure: {}", m, cause);
                          }
                      }, MoreExecutors.directExecutor());
                  });
}
 

/** Remove dirs & files needed for test. */
private static void cleanup(Path dir) {
    try {
        if (Files.isDirectory(dir)) {
            try (Stream<Path> s = Files.list(dir)) {
                s.forEach( p -> cleanup(p));
            }
        }
        Files.delete(dir);
    } catch (IOException x) {
        fail(x.toString());
    }
}
 

private static List<Pair<CompileCodeTestCase, Class<? extends Throwable>>>
        createTestCasesIncorrectBci() {
    List<Pair<CompileCodeTestCase, Class<? extends Throwable>>> result
            = new ArrayList<>();
    try {
        Class<?> aClass = DummyClass.class;
        Object receiver = new DummyClass();
        Method method = aClass.getMethod("dummyInstanceFunction");
        // greater than bytecode.length
        byte[] bytecode = CompilerToVMHelper.getBytecode(CTVMUtilities
                .getResolvedMethod(method));
        Stream.of(
                // greater than bytecode.length
                bytecode.length + 4,
                bytecode.length + 50,
                bytecode.length + 200,
                // negative cases
                -4, -50, -200)
                .map(bci -> new Pair<CompileCodeTestCase,
                        Class<? extends Throwable>>(
                        new CompileCodeTestCase(receiver, method, bci),
                        IllegalArgumentException.class))
                .collect(Collectors.toList());
    } catch (NoSuchMethodException e) {
        throw new Error("TEST BUG : " + e.getMessage(), e);
    }
    return result;
}
 

@DataProvider(name = "Stream.limit")
@SuppressWarnings("rawtypes")
public static Object[][] sliceFunctionsDataProvider() {
    Function<String, String> f = s -> String.format(s, SKIP_LIMIT_SIZE);

    List<Object[]> data = new ArrayList<>();

    data.add(new Object[]{f.apply("Stream.limit(%d)"),
            (UnaryOperator<Stream>) s -> s.limit(SKIP_LIMIT_SIZE)});
    data.add(new Object[]{f.apply("Stream.skip(%1$d).limit(%1$d)"),
            (UnaryOperator<Stream>) s -> s.skip(SKIP_LIMIT_SIZE).limit(SKIP_LIMIT_SIZE)});

    return data.toArray(new Object[0][]);
}
 

@Override
public List<URI> getServiceDetails() {
    //fetch the URI.
    return Futures.getAndHandleExceptions(k8sClient.getStatusOfPodWithLabel(NAMESPACE, "component", PRAVEGA_CONTROLLER_LABEL)
                                                   .thenApply(statuses -> statuses.stream()
                                                                                 .flatMap(s -> Stream.of(URI.create(TCP + s.getPodIP() + ":" + CONTROLLER_GRPC_PORT),
                                                                                                         URI.create(TCP + s.getPodIP() + ":" + CONTROLLER_REST_PORT)))
                                                                                 .collect(Collectors.toList())),
                                          t -> new TestFrameworkException(RequestFailed, "Failed to fetch ServiceDetails for pravega-controller", t));
}
 

public Stream<Field> allFieldsOfClassLineage(Class<?> testClass) {
    return getClassLineage(testClass).stream()
        .sequential()
        .flatMap(aClass -> Arrays.stream(aClass.getDeclaredFields()))
        .peek(field -> field.setAccessible(true));

}
 

/**
 * Generic procedure for discovering request/exception handlers and request/response interceptors
 * from a controller's methods.
 *
 * Applies method discovery logic consistently for all mapping types:
 * <ul>
 *     <li>resolve a {@link Predicate} of {@link HandlerInput} from the method</li>
 *     <li>delegate responsibility to the underlying handler, but guard it with the predicate</li>
 *     <li>look for the {@link Priority} annotation on each method</li>
 *     <li>order each handler in the controller by its priority</li>
 *     <li>methods not annotated with {@link Priority} are considered to have priority 0</li>
 * </ul>
 *
 * @param controller scanned for methods with mappers
 * @param resolvers set of resolvers
 * @param guardBuilder supplies a {@link Guard.Builder} for this mapping type
 * @param <T> type of handler/interceptor/etc. being discovered, e.g. {@link RequestInterceptor}
 * @param <G> type of guard, e.g. {@link RequestInterceptorGuard}
 * @param <B> type of guard builder, e.g. {@link RequestInterceptorGuard#builder()}
 * @return stream of constructed delegates, ordered by priority
 */
protected <T, G extends Guard<T>, B extends Guard.Builder<B, T, G>> Stream<G> find(
    Object controller,
    Set<? extends Resolver<ControllerMethodContext, T>> resolvers,
    Supplier<B> guardBuilder) {

    return Arrays.stream(controller.getClass().getMethods())
        .map(method -> ControllerMethodContext.builder()
            .withSkillContext(skillContext)
            .withController(controller)
            .withMethod(method)
            .build())
        .flatMap(context -> {
            Predicate<HandlerInput> predicate = findPredicates(context).orElse(TRUE);

            return resolvers.stream()
                .flatMap(resolver -> resolver.resolve(context).map(Stream::of).orElse(Stream.empty()))
                .map(delegate -> guardBuilder.get()
                    .withDelegate(delegate)
                    .withPredicate(predicate)
                    .withPriority(Optional.ofNullable(context.getMethod().getAnnotation(Priority.class))
                        .map(Priority::value)
                        .orElse(0))) // default to the '0' bucket for methods not annotated with Priority
                .map(Guard.Builder::<G>build);
        })
        // sort in descending order, so "higher priority" is more intuitive
        .sorted((a, b) -> -1 * Integer.compare(a.getPriority(), b.getPriority()));
}