Example usage for java.util.stream Collectors reducing

Introduction

In this page you can find the example usage for java.util.stream Collectors reducing.

Prototype

public static <T, U> Collector<T, ?, U> reducing(U identity, Function<? super T, ? extends U> mapper,
        BinaryOperator<U> op) 

Source Link

Document

Returns a Collector which performs a reduction of its input elements under a specified mapping function and BinaryOperator .

Usage

From source file:Main.java

public static void main(String... args) {
    int o = Food.menu.stream().collect(Collectors.reducing(0, Food::getCalories, Integer::sum));
    System.out.println(o);/*from ww w .  j  av a  2s .co  m*/

}

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From source file:Main.java

public static void main(String... args) {
    int o = Food.menu.stream()
            .collect(Collectors.reducing(0, Food::getCalories, (Integer i, Integer j) -> i + j));
    System.out.println(o);/*  www .  ja  va2 s  . c o  m*/

}

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From source file:Main.java

public static void main(String[] args) {
    List<Person> roster = createRoster();

    System.out.println("Total age by gender:");
    Map<Person.Sex, Integer> totalAgeByGender = roster.stream().collect(
            Collectors.groupingBy(Person::getGender, Collectors.reducing(0, Person::getAge, Integer::sum)));

    List<Map.Entry<Person.Sex, Integer>> totalAgeByGenderList = new ArrayList<>(totalAgeByGender.entrySet());

    totalAgeByGenderList.stream()/* w w w.  ja v a 2 s.  co m*/
            .forEach(e -> System.out.println("Gender: " + e.getKey() + ", Total Age: " + e.getValue()));

}

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From source file:com.netflix.spinnaker.clouddriver.kubernetes.v2.caching.KubernetesV2SearchProvider.java

private Map<String, List<String>> getKeysRelatedToLogicalMatches(String matchQuery) {
    return logicalTypes.stream().map(type -> cacheUtils.getAllDataMatchingPattern(type, matchQuery).stream()
            .map(e -> e.getRelationships().values().stream().flatMap(Collection::stream)
                    .filter(Objects::nonNull).map(k -> new ImmutablePair<>(k, e.getId())))
            .flatMap(x -> x)).flatMap(x -> x)
            .collect(Collectors.groupingBy(Pair::getLeft, Collectors.reducing(Collections.emptyList(),
                    i -> Collections.singletonList(i.getRight()), (a, b) -> {
                        List<String> res = new ArrayList<>();
                        res.addAll(a);//w  w w . j  ava2s.  c  o  m
                        res.addAll(b);
                        return res;
                    })));
}

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From source file:com.diversityarrays.kdxplore.data.kdx.CurationDataCollector.java

public CurationDataCollector(KdxploreDatabase kdxdb, Trial trial, boolean fullDetails)
        throws IOException, KdxploreConfigException {
    this.trial = trial;

    int trialId = trial.getTrialId();
    this.deviceIdentifiers = kdxdb.getDeviceIdentifiers();

    deviceIdentifierById.clear();/*from w w  w  .  j ava  2s .c  om*/
    for (DeviceIdentifier d : deviceIdentifiers) {
        deviceIdentifierById.put(d.getDeviceIdentifierId(), d);
    }

    //        ProgressUpdater progressUpdater;
    //        kdxdb.getKDXploreKSmartDatabase().collectPlotsFor(trial, 
    //                SampleGroupChoice.ANY_SAMPLE_GROUP, 
    //                KDSmartDatabase.WithPlotAttributesOption.WITH_PLOT_ATTRIBUTES,
    //                KDSmartDatabase.WithTraitOption.ALL_WITH_TRAITS,
    //                progressUpdater);
    //        
    //        this.plots = kdxdb.getPlots(trial, SampleGroupChoice.ANY_SAMPLE_GROUP,
    //                KDSmartDatabase.WithPlotAttributesOption.WITH_PLOT_ATTRIBUTES);

    Closure<Pair<WhyMissing, MediaFileRecord>> reportMissing = new Closure<Pair<WhyMissing, MediaFileRecord>>() {
        @Override
        public void execute(Pair<WhyMissing, MediaFileRecord> arg0) {
            // TODO Auto-generated method stub

        }
    };
    Map<Integer, Plot> plotById = DatabaseUtil.collectPlotsIncludingMediaFiles(
            kdxdb.getKDXploreKSmartDatabase(), trialId, "CurationDataCollector",
            SampleGroupChoice.ANY_SAMPLE_GROUP, reportMissing);
    this.plots = new ArrayList<>(plotById.values());

    this.countByTagLabel = Collections.unmodifiableMap(plots.stream()
            .flatMap(plot -> plot.getTagsBySampleGroup().entrySet().stream())
            .flatMap(e -> e.getValue().stream())
            .collect(Collectors.groupingBy(Tag::getLabel, Collectors.reducing(0, e -> 1, Integer::sum))));

    collectPlotPositionIdentifiers(plots);

    trialAttributes = kdxdb.getTrialAttributes(trialId);

    KDSmartDatabase kdsdb = kdxdb.getKDXploreKSmartDatabase();

    plotAttributes = kdsdb.getAllPlotAttributesForTrial(trialId);
    traitInstances = kdsdb.getTraitInstances(trialId, KDSmartDatabase.WithTraitOption.ALL_WITH_TRAITS);

    //        tagById.clear();
    //        for (Tag tag : kdsdb.getAllTags()) {
    //            tagById.put(tag.getTagId(), tag);
    //        }

    //        collectTagPlotUsage(trialId, kdsdb);

    //        collectMediaFileRecords(trialId, kdsdb);

    loadSampleGroups(kdxdb, trialId, fullDetails);
}

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