Java8-Stream-No.12

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import java.util.ArrayList;import java.util.Arrays;import java.util.List;import java.util.UUID;import java.util.concurrent.ForkJoinPool;import java.util.concurrent.TimeUnit;public class Streams12 {    public static void main(String[] args) {        List<String> strings = Arrays.asList("a1", "a2", "b1", "c2", "c1");//        test1();//        test2(strings);        test3(strings);//        test4();    }    private static void test4() {        List<String> values = new ArrayList<>(100);        for (int i = 0; i < 100; i++) {            UUID uuid = UUID.randomUUID();            values.add(uuid.toString());        }        // sequential        long t0 = System.nanoTime();        long count = values            .parallelStream()            .sorted((s1, s2) -> {                System.out.format("sort:    %s <> %s [%s]\n", s1, s2, Thread.currentThread().getName());                return s1.compareTo(s2);            })            .count();        System.out.println(count);        long t1 = System.nanoTime();        long millis = TimeUnit.NANOSECONDS.toMillis(t1 - t0);        System.out.println(String.format("parallel sort took: %d ms", millis));    }    private static void test3(List<String> strings) {        strings            .parallelStream()            .filter(s -> {                System.out.format("filter:  %s [%s]\n", s, Thread.currentThread().getName());                return true;            })            .map(s -> {                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()));    }    private static void test2(List<String> strings) {        strings            .parallelStream()            .filter(s -> {                System.out.format("filter:  %s [%s]\n", s, Thread.currentThread().getName());                return true;            })            .map(s -> {                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()));    }    private static void test1() {        // -Djava.util.concurrent.ForkJoinPool.common.parallelism=5        ForkJoinPool commonPool = ForkJoinPool.commonPool();        System.out.println(commonPool.getParallelism());    }}
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