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:Main.java

public static void main(String[] args) {
    Stream<String> s = Stream.empty();
    s.limit(10).forEach(System.out::println);

}

From source file:Main.java

public static void main(String[] args) {
    Stream<String> stream = Stream.empty();
    stream.forEach(System.out::println);
}

From source file:es.uam.eps.ir.ranksys.examples.RerankerExample.java

public static void main(String[] args) throws Exception {
    String trainDataPath = args[0];
    String featurePath = args[1];
    String recIn = args[2];// www .j  a  v a 2 s  .c om

    int cutoff = 100;
    PreferenceData<Long, Long> trainData = SimplePreferenceData
            .load(SimpleRatingPreferencesReader.get().read(trainDataPath, lp, lp));
    FeatureData<Long, String, Double> featureData = SimpleFeatureData
            .load(SimpleFeaturesReader.get().read(featurePath, lp, sp));

    Map<String, Supplier<Reranker<Long, Long>>> rerankersMap = new HashMap<>();

    rerankersMap.put("MMR", () -> {
        double lambda = 0.5;
        ItemDistanceModel<Long> dist = new JaccardFeatureItemDistanceModel<>(featureData);
        return new MMR<>(lambda, cutoff, dist);
    });

    rerankersMap.put("xQuAD", () -> {
        double lambda = 0.5;
        IntentModel<Long, Long, String> intentModel = new FeatureIntentModel<>(trainData, featureData);
        AspectModel<Long, Long, String> aspectModel = new ScoresAspectModel<>(intentModel);
        return new XQuAD<>(aspectModel, lambda, cutoff, true);
    });

    rerankersMap.put("RxQuAD", () -> {
        double alpha = 0.5;
        double lambda = 0.5;
        IntentModel<Long, Long, String> intentModel = new FeatureIntentModel<>(trainData, featureData);
        AspectModel<Long, Long, String> aspectModel = new ScoresRelevanceAspectModel<>(intentModel);
        return new AlphaXQuAD<>(aspectModel, alpha, lambda, cutoff, true);
    });

    rerankersMap.put("PM", () -> {
        double alpha = 0.5;
        double lambda = 0.9;
        BinomialModel<Long, Long, String> binomialModel = new BinomialModel<>(false, Stream.empty(), trainData,
                featureData, alpha);
        return new PM<>(featureData, binomialModel, lambda, cutoff);
    });

    RecommendationFormat<Long, Long> format = new SimpleRecommendationFormat<>(lp, lp);

    rerankersMap.forEach(Unchecked.biConsumer((name, rerankerSupplier) -> {
        String recOut = Paths.get(Paths.get(recIn).getParent().toString(),
                String.format("%s-%s", name, FilenameUtils.getName(recIn))).toString();
        System.out.printf("running %s, output to %s\n", name, recOut);
        Reranker<Long, Long> reranker = rerankerSupplier.get();
        try (RecommendationFormat.Writer<Long, Long> writer = format.getWriter(recOut)) {
            format.getReader(recIn).readAll().map(rec -> reranker.rerankRecommendation(rec, cutoff))
                    .forEach(Unchecked.consumer(writer::write));
        }
    }));
}

From source file:Main.java

public static <T> Stream<T> toStream(Optional<T> optional) {
    if (optional.isPresent()) {
        return Stream.of(optional.get());
    }/*w w w . j  av  a 2 s  . co  m*/
    return Stream.empty();
}

From source file:Main.java

public static <T> Stream<List<T>> batches(List<T> source, int length) {
    if (length <= 0)
        throw new IllegalArgumentException("length = " + length);
    int size = source.size();
    if (size <= 0)
        return Stream.empty();
    int fullChunks = (size - 1) / length;
    return IntStream.range(0, fullChunks + 1)
            .mapToObj(n -> source.subList(n * length, n == fullChunks ? size : (n + 1) * length));
}

From source file:pe.chalk.telegram.util.JSONHelper.java

public static <T> Stream<T> buildStream(final JSONArray array, Class<? extends T> typeClass) {
    if (array == null)
        return Stream.empty();

    final Stream.Builder<T> builder = Stream.builder();
    for (int i = 0; i < array.length(); i++) {
        if (array.isNull(i))
            continue;

        final Object item = array.get(i);
        if (typeClass.isInstance(item))
            builder.add(typeClass.cast(item));
    }//from  w  w w.j a v  a 2  s .c om
    return builder.build();
}

From source file:Main.java

/**
 * Split the list and return the stream with the resultant lists.
 *
 * @param list to be split//from  www. j  a  v  a 2 s.com
 * @param size of each list after splitting.
 * @param <T>  type of list.
 * @return {@link Stream} of {@link List}s
 */
public static <T> Stream<List<T>> splitListStream(final List<T> list, final int size) {

    if (size <= 0) {
        throw new IllegalArgumentException("Invalid Split Size");
    }

    final int listSize = list.size();

    if (listSize == 0) {
        return Stream.empty();
    }

    return IntStream.rangeClosed(0, (listSize - 1) / size)
            .mapToObj(n -> list.subList(n * size, Math.min((n + 1) * size, listSize)));
}

From source file:org.kaaproject.kaa.examples.common.DemoBuilder.java

default Stream<Pair<CommandLine, String>> getAdditionalCommandsAndParams() {
    return Stream.empty();
}

From source file:Main.java

/**
 * This method is a shortcut for {@code c.stream()} if c is not {@code null}. If c is {@code null},
 * this method will return an empty stream.
 *
 * @param c   Collection to create a Stream from. If {@code null}, an empty stream will be returned.
 * @param <T> Type of elements in collection.
 * @return Stream created from collection {@code c}.
 *///  w  ww . j  a v  a 2 s.c o  m
public static <T> Stream<T> $(Collection<T> c) {
    if (c == null) {
        return Stream.empty();
    }
    // else
    return c.stream();
}

From source file:us.askplatyp.kb.lucene.wikidata.mapping.ISBNStatementMapper.java

@Override
public Stream<Field> mapMainStringValue(StringValue value) throws InvalidWikibaseValueException {
    String ISBN = ISBNValidator.getInstance().validate(value.getString());
    if (ISBN == null) {
        return Stream.empty();
    }/*www.j ava 2s  .  co m*/
    return Stream.of(new StringField("isbn", ISBN, Field.Store.YES));
}