Example usage for java.util List parallelStream

Introduction

In this page you can find the example usage for java.util List parallelStream.

Prototype

default Stream<E> parallelStream()

Source Link

Document

Returns a possibly parallel Stream with this collection as its source.

Usage

From source file:Main.java

public static void main(String[] args) {
    List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);
    int sum = numbers.parallelStream().filter(n -> n % 2 == 1).map(n -> n * n).reduce(0, Integer::sum);

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

From source file:Main.java

public static void main(String[] args) {
    List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5);

    double sum = numbers.parallelStream().reduce(0.0, (partialSum, a) -> partialSum + a, Double::sum);
    System.out.println(sum);/*from w  ww.  ja v  a 2 s. c om*/

}

From source file:Main.java

public static void main(String[] args) {
    List<String> liste = Arrays.asList("CSS", "HTML", "Davut", null);

    liste.parallelStream()// Parallel stuff uses Fork-Join
            .filter(e -> (!Objects.equals(e, null))) // lazy & parallel
            .filter(e -> (e.length() > 3)) // lazy & parallel
            .forEach(e -> { // sequential & eagerly
                System.out.println("Bigger length than 3 in List: " + e);
            });//from   w ww .  java 2  s  . co  m
}

From source file:Main.java

public static void main(String[] args) {
    List<String> liste = Arrays.asList("XML", "HTML", "CSS", null);

    liste.parallelStream()// Parallel stuff uses Fork-Join
            .filter(e -> (!Objects.equals(e, null))) // lazy & parallel
            .filter(e -> (e.length() > 3)) // lazy & parallel
            .forEach(e -> { // sequential & eagerly
                System.out.println("Bigger length than 3 in List: " + e);
            });//from   w ww .  j  a v a 2  s  .c  o m

}

From source file:Main.java

public static void main(String[] args) throws Exception {
    List<String> strings = Arrays.asList("a1", "a2", "b1", "c2", "c1");

    strings.parallelStream().filter(s -> {
        System.out.format("filter:  %s [%s]\n", s, Thread.currentThread().getName());
        return true;
    }).map(s -> {//from  w  w  w.  jav  a2 s  .c om
        System.out.format("map:     %s [%s]\n", s, Thread.currentThread().getName());
        return s.toUpperCase();
    }).forEach(s -> System.out.format("forEach: %s [%s]\n", s, Thread.currentThread().getName()));

}

From source file:Main.java

public static void main(String[] args) throws Exception {
    List<String> strings = Arrays.asList("a1", "a2", "b1", "c2", "c1");

    strings.parallelStream().filter(s -> {
        System.out.format("filter:  %s [%s]\n", s, Thread.currentThread().getName());
        return true;
    }).map(s -> {// w  ww  . j  ava  2s  . c om
        System.out.format("map:     %s [%s]\n", s, Thread.currentThread().getName());
        return s.toUpperCase();
    }).sorted((s1, s2) -> {
        System.out.format("sort:    %s <> %s [%s]\n", s1, s2, Thread.currentThread().getName());
        return s1.compareTo(s2);
    }).forEach(s -> System.out.format("forEach: %s [%s]\n", s, Thread.currentThread().getName()));
}

From source file:Main.java

public static void main(String[] args) {
    List<String> terms = Arrays.asList("this", "is", "is", "a");

    Map<String, Integer> result = terms.parallelStream().flatMap(s -> Arrays.asList(s.split(" ")).stream())
            .collect(Collectors.toConcurrentMap(w -> w.toLowerCase(), w -> 1, Integer::sum));
    System.out.println(result);//from   ww  w. ja  va 2  s.  c o  m
}

From source file:Main.java

public static void main(String[] args) {

    List<Integer> l = Arrays.asList(4, 3, 5, 7, 2, 2, 3, 5);

    l.stream().reduce((a, b) -> a + b).ifPresent(System.out::println);

    l.parallelStream().reduce((a, b) -> a + b).ifPresent(System.out::println);

    System.out.println("isParallel list.stream(): " + l.stream().isParallel());

    System.out.println("isParallel list.stream().parallel(): " + l.stream().parallel().isParallel());

    System.out.println("isParallel list.parallelStream(): " + l.parallelStream().isParallel());

    System.out.println(/*  w  w w . j  a  v  a  2 s  .c  o  m*/
            "isParallel list.parallelStream().sequential(): " + l.parallelStream().sequential().isParallel());
}

From source file:Main.java

public static void main(String[] args) {
    List<Person> roster = createRoster();
    double average = roster.parallelStream().filter(p -> p.getGender() == Person.Sex.MALE)
            .mapToInt(Person::getAge).average().getAsDouble();

    System.out.println("Average age of male members in parallel: " + average);
}

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));

    Integer ageSum = persons.parallelStream().reduce(0, (sum, p) -> {
        System.out.format("accumulator: sum=%s; person=%s\n", sum, p);
        return sum += p.age;
    }, (sum1, sum2) -> {//from  w ww.  j ava2  s  .  co  m
        System.out.format("combiner: sum1=%s; sum2=%s\n", sum1, sum2);
        return sum1 + sum2;
    });

    System.out.println(ageSum);
}