Example usage for java.util.stream Collectors toMap

Introduction

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

Prototype

public static <T, K, U> Collector<T, ?, Map<K, U>> toMap(Function<? super T, ? extends K> keyMapper,
        Function<? super T, ? extends U> valueMapper, BinaryOperator<U> mergeFunction) 

Source Link

Document

Returns a Collector that accumulates elements into a Map whose keys and values are the result of applying the provided mapping functions to the input elements.

Usage

From source file:Main.java

public static void main(String[] args) {
    Map<Employee.Gender, Long> countByGender = Employee.persons().stream().collect(
            Collectors.toMap(Employee::getGender, p -> 1L, (oldCount, newCount) -> newCount + oldCount));

    System.out.println(countByGender);
}

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From source file:Main.java

public static void main(String[] args) {
    Map<Employee.Gender, String> genderToNamesMap = Employee.persons().stream()
            .collect(Collectors.toMap(Employee::getGender, Employee::getName,
                    (oldValue, newValue) -> String.join(", ", oldValue, newValue)));
    System.out.println(genderToNamesMap);
}

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From source file:Main.java

public static void main(String[] args) {
    Map<Employee.Gender, Employee> highestEarnerByGender = Employee.persons().stream().collect(Collectors.toMap(
            Employee::getGender, Function.identity(),
            (oldPerson, newPerson) -> newPerson.getIncome() > oldPerson.getIncome() ? newPerson : oldPerson));
    System.out.println(highestEarnerByGender);
}

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From source file:Main.java

public static void main(String[] args) throws Exception {
    List<Person> persons = Arrays.asList(new Person("Max", 18), new Person("Peter", 23),
            new Person("Pamela", 23), new Person("David", 12));
    Map<Integer, String> map = persons.stream()
            .collect(Collectors.toMap(p -> p.age, p -> p.name, (name1, name2) -> name1 + ";" + name2));

    System.out.println(map);//w ww.ja  v a 2  s  .  c  om
}

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From source file:Main.java

@SafeVarargs
public static <K, V> Map<K, V> unionMap(boolean preserved, Map<K, V>... maps) {
    return Stream.of(maps).map(Map::entrySet).flatMap(Collection::stream).collect(Collectors
            .toMap(Map.Entry::getKey, Map.Entry::getValue, preserved ? preserveMerger() : abandonMerger()));
}

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From source file:com.thinkbiganalytics.config.rest.controller.ConfigurationController.java

/**
 * Get the configuration information/*w  ww .j a  v a  2  s .co  m*/
 *
 * @return A map of name value key pairs
 */
@GET
@Path("/properties")
@Produces(MediaType.APPLICATION_JSON)
@ApiOperation("Gets the current Kylo configuration.")
@ApiResponses({
        @ApiResponse(code = 200, message = "Returns the configuration parameters.", response = Map.class) })
public Response getConfiguration() {
    final Map<String, Object> properties;

    if ((request.getRemoteAddr().equals("127.0.0.1") || request.getRemoteAddr().equals("0:0:0:0:0:0:0:1"))
            && env instanceof AbstractEnvironment) {
        properties = StreamSupport.stream(((AbstractEnvironment) env).getPropertySources().spliterator(), false)
                .filter(source -> source instanceof PropertiesPropertySource)
                .flatMap(source -> ((PropertiesPropertySource) source).getSource().entrySet().stream())
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (value1, value2) -> value1));
    } else {
        properties = Collections.emptyMap();
    }

    return Response.ok(properties).build();
}

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From source file:jvmoptions.OptionAnalyzer.java

static Map<String, Map<String, String>> makeMap(String root) throws Exception {
    Path start = FileSystems.getDefault().getPath(root);
    File dir = start.toFile();/*from  www  . jav a  2s  .  c  o  m*/
    if (dir.exists() == false || dir.isDirectory() == false) {
        System.err.printf("%s doesn't exists or doesn't dir %n", root);
        System.err.println("run gradle task below");
        System.err.println("gradlew getSrcs");
        System.exit(1);
    }

    return Files.walk(start).map(Path::toFile).filter(File::isFile).filter(f -> f.getName().endsWith(".hpp"))
            .map(File::toPath).parallel().filter(OptionAnalyzer::contains).map(OptionAnalyzer::parse)
            .map(Map::entrySet).flatMap(Collection::stream)
            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, OptionAnalyzer::merge));
}

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From source file:com.adobe.acs.commons.data.Spreadsheet.java

/**
 * Parse out the input file synchronously for easier unit test validation
 *
 * @return List of files that will be imported, including any renditions
 * @throws IOException if the file couldn't be read
 *//*from  w ww  .  ja  va2 s  . com*/
private void parseInputFile(InputStream file) throws IOException {

    XSSFWorkbook workbook = new XSSFWorkbook(file);

    final XSSFSheet sheet = workbook.getSheetAt(0);
    rowCount = sheet.getLastRowNum();
    final Iterator<Row> rows = sheet.rowIterator();

    Row firstRow = rows.next();
    headerRow = readRow(firstRow).stream().map(Variant::toString).map(this::convertHeaderName)
            .collect(Collectors.toList());
    headerTypes = readRow(firstRow).stream().map(Variant::toString)
            .collect(Collectors.toMap(this::convertHeaderName, this::detectTypeFromName, this::upgradeToArray));

    Iterable<Row> remainingRows = () -> rows;
    dataRows = StreamSupport.stream(remainingRows.spliterator(), false).map(this::buildRow)
            .filter(Optional::isPresent).map(Optional::get).collect(Collectors.toList());
}

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From source file:com.netflix.spinnaker.clouddriver.google.controllers.GoogleNamedImageLookupController.java

@VisibleForTesting
public static Map<String, String> buildTagsMap(Image image) {
    Map<String, String> tags = new HashMap<>();

    String description = image.getDescription();
    // For a description of the form:
    // key1: value1, key2: value2, key3: value3
    // we'll build a map associating each key with
    // its associated value
    if (description != null) {
        tags = Arrays.stream(description.split(",")).filter(token -> token.contains(": "))
                .map(token -> token.split(": ", 2))
                .collect(Collectors.toMap(token -> token[0].trim(), token -> token[1].trim(), (a, b) -> b));
    }//from  ww  w  . jav  a2s  .  c  o m

    Map<String, String> labels = image.getLabels();
    if (labels != null) {
        tags.putAll(labels);
    }

    return tags;
}

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From source file:com.thinkbiganalytics.auth.jaas.config.JaasAuthConfig.java

@Bean(name = "jaasConfiguration")
public javax.security.auth.login.Configuration jaasConfiguration(
        Optional<List<LoginConfiguration>> loginModuleEntries) {
    // Generally the entries will be null only in situations like unit/integration tests.
    if (loginModuleEntries.isPresent()) {
        List<LoginConfiguration> sorted = new ArrayList<>(loginModuleEntries.get());
        sorted.sort(new AnnotationAwareOrderComparator());

        Map<String, AppConfigurationEntry[]> merged = sorted.stream()
                .map(c -> c.getAllApplicationEntries().entrySet()).flatMap(s -> s.stream())
                .collect(Collectors.toMap(e -> e.getKey(), e -> e.getValue(), ArrayUtils::addAll));
        return new InMemoryConfiguration(merged);
    } else {/*w  ww. j ava2  s.  c  o m*/
        return new InMemoryConfiguration(Collections.emptyMap());
    }
}

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