Example usage for java.util.stream Stream empty

Introduction

In this page you can find the example usage for java.util.stream Stream empty.

Prototype

public static <T> Stream<T> empty()

Source Link

Document

Returns an empty sequential Stream .

Usage

From source file:com.ikanow.aleph2.data_model.utils.CrudUtils.java

protected static Stream<Tuple2<String, Object>> recursiveQueryBuilder_init(final Object bean,
        final boolean denest) {
    if (null == bean) { // (for handling JSON, where you don't have a bean)
        return Stream.of();
    }/*from   ww  w.  ja v a2 s . c o m*/
    //TODO (ALEPH-22) sometimes you need to nest the functionality and sometimes you don't... (eg updates normally not? queries normally
    // but actually the behavior is different .. to test this desnest==false, need to bring mongojack into the test context
    // so can test it for MongoDB

    return Arrays.stream(bean.getClass().getDeclaredFields()).filter(f -> !Modifier.isStatic(f.getModifiers())) // (ignore static fields)
            .flatMap(field_accessor -> {
                try {
                    field_accessor.setAccessible(true);
                    Object val = field_accessor.get(bean);

                    return Patterns.match(val).<Stream<Tuple2<String, Object>>>andReturn()
                            .when(v -> null == v, v -> Stream.empty())
                            .when(String.class, v -> Stream.of(Tuples._2T(field_accessor.getName(), v)))
                            .when(Number.class, v -> Stream.of(Tuples._2T(field_accessor.getName(), v)))
                            .when(Boolean.class, v -> Stream.of(Tuples._2T(field_accessor.getName(), v)))
                            .when(Collection.class, l -> Stream.of(Tuples._2T(field_accessor.getName(), l))) // (note can't denest objects/bean templates, that will exception out)
                            .when(Map.class, v -> Stream.of(Tuples._2T(field_accessor.getName(), v)))
                            .when(Multimap.class, v -> Stream.of(Tuples._2T(field_accessor.getName(), v)))
                            // OK if it's none of these supported types that we recognize, then assume it's a bean and recursively de-nest it
                            .when(BeanTemplate.class, v -> denest,
                                    v -> recursiveQueryBuilder_recurse(field_accessor.getName(), v))
                            .when(BeanTemplate.class, v -> Stream.of(Tuples._2T(field_accessor.getName(), v)))
                            .when(v -> denest,
                                    v -> recursiveQueryBuilder_recurse(field_accessor.getName(),
                                            BeanTemplate.of(v)))
                            .otherwise(
                                    v -> Stream.of(Tuples._2T(field_accessor.getName(), BeanTemplate.of(v))));
                } catch (Exception e) {
                    return null;
                }
            });
}

From source file:org.trellisldp.http.AbstractTrellisHttpResourceTest.java

@Test
public void testDeleteNoChildren1() {
    when(mockVersionedResource.getInteractionModel()).thenReturn(LDP.BasicContainer);
    when(mockVersionedResource.stream(eq(LDP.PreferContainment))).thenAnswer(inv -> Stream.empty());

    final Response res = target(RESOURCE_PATH).request().delete();

    assertEquals(SC_NO_CONTENT, res.getStatus(), "Unexpected response code!");
}

From source file:org.trellisldp.http.AbstractTrellisHttpResourceTest.java

@Test
public void testDeleteNoChildren2() {
    when(mockVersionedResource.getInteractionModel()).thenReturn(LDP.Container);
    when(mockVersionedResource.stream(eq(LDP.PreferContainment))).thenAnswer(inv -> Stream.empty());

    final Response res = target(RESOURCE_PATH).request().delete();

    assertEquals(SC_NO_CONTENT, res.getStatus(), "Unexpected response code!");
}

From source file:com.ikanow.aleph2.data_import_manager.analytics.actors.DataBucketAnalyticsChangeActor.java

/** Combine the analytic thread level results and the per-job results into a single reply
 * @param top_level//from  w  ww . j  a  va 2  s .c o m
 * @param per_job
 * @param source
 * @return
 */
protected final static CompletableFuture<BucketActionReplyMessage> combineResults(
        final CompletableFuture<BasicMessageBean> top_level,
        final List<CompletableFuture<BasicMessageBean>> per_job, final String source) {
    if (per_job.isEmpty()) {
        return top_level.thenApply(reply -> new BucketActionHandlerMessage(source, reply));
    } else { // slightly more complex:

        // First off wait for them all to complete:
        final CompletableFuture<?>[] futures = per_job.toArray(new CompletableFuture<?>[0]);

        return top_level.thenCombine(CompletableFuture.allOf(futures), (thread, __) -> {
            List<BasicMessageBean> replies = Stream.concat(Lambdas.get(() -> {
                if (thread.success() && ((null == thread.message()) || thread.message().isEmpty())) {
                    // Ignore top level, it's not very interesting
                    return Stream.empty();
                } else
                    return Stream.of(thread);
            }), per_job.stream().map(cf -> cf.join())

            ).collect(Collectors.toList());

            return (BucketActionReplyMessage) new BucketActionCollectedRepliesMessage(source, replies,
                    Collections.emptySet(), Collections.emptySet());
        }).exceptionally(t -> {
            return (BucketActionReplyMessage) new BucketActionHandlerMessage(source,
                    ErrorUtils.buildErrorMessage(DataBucketAnalyticsChangeActor.class.getSimpleName(), source,
                            ErrorUtils.getLongForm("{0}", t)));
        });
    }
}

From source file:com.ikanow.aleph2.data_import_manager.analytics.actors.DataBucketAnalyticsChangeActor.java

/** Creates a query component to get all the shared library beans i need
 * @param bucket/*from  w  w w . java  2 s.c o m*/
 * @param cache_tech_jar_only
 * @return
 */
protected static QueryComponent<SharedLibraryBean> getQuery(final DataBucketBean bucket,
        final boolean cache_tech_jar_only) {
    final String technology = getAnalyticsTechnologyName(bucket).get(); //(non-empty by construction)
    final SingleQueryComponent<SharedLibraryBean> tech_query = CrudUtils.anyOf(SharedLibraryBean.class)
            .when(SharedLibraryBean::_id, technology).when(SharedLibraryBean::path_name, technology);

    final Stream<SingleQueryComponent<SharedLibraryBean>> other_libs = cache_tech_jar_only ? Stream.empty()
            : Optionals.ofNullable(bucket.analytic_thread().jobs()).stream()
                    .flatMap(a_job -> Stream.concat(
                            Optional.ofNullable(a_job.module_name_or_id()).map(Stream::of)
                                    .orElse(Stream.empty()),
                            Optionals.ofNullable(a_job.library_names_or_ids()).stream()))
                    .map(name -> {
                        return CrudUtils.anyOf(SharedLibraryBean.class).when(SharedLibraryBean::_id, name)
                                .when(SharedLibraryBean::path_name, name);
                    });

    return CrudUtils.<SharedLibraryBean>anyOf(Stream.concat(Stream.of(tech_query), other_libs));
}

From source file:org.trellisldp.http.AbstractLdpResourceTest.java

@Test
public void testDeleteNoChildren1() {
    when(mockVersionedResource.getInteractionModel()).thenReturn(LDP.BasicContainer);
    when(mockVersionedResource.stream(eq(LDP.PreferContainment))).thenAnswer(inv -> Stream.empty());

    final Response res = target(RESOURCE_PATH).request().delete();

    assertEquals(NO_CONTENT, res.getStatusInfo());
}

From source file:org.trellisldp.http.AbstractLdpResourceTest.java

@Test
public void testDeleteNoChildren2() {
    when(mockVersionedResource.getInteractionModel()).thenReturn(LDP.Container);
    when(mockVersionedResource.stream(eq(LDP.PreferContainment))).thenAnswer(inv -> Stream.empty());

    final Response res = target(RESOURCE_PATH).request().delete();

    assertEquals(NO_CONTENT, res.getStatusInfo());
}