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());
}
}
转载于:https://www.cnblogs.com/bilaisheng/p/10210926.html
