// concurrent/ParallelStreamPuzzle2.java

// (c)2017 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

import java.util.*;

import java.util.function.*;

import java.util.stream.*;

import java.util.concurrent.*;

import java.util.concurrent.atomic.*;

import java.nio.file.*;

public class ParallelStreamPuzzle2 {

public static final Deque<String> trace =

new ConcurrentLinkedDeque<>();

static class

IntGenerator implements Supplier<Integer> {

private AtomicInteger current =

new AtomicInteger();

public Integer get() {

trace.add(current.get() + ": " +

Thread.currentThread().getName());

return current.getAndIncrement();

}

}

public static void

main(String[] args) throws Exception {

List<Integer> x =

Stream.generate(new IntGenerator())

.limit(10)

.parallel()

.collect(Collectors.toList());

System.out.println(x);

Files.write(Paths.get("PSP2.txt"), trace);

}

}

/* Output:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

*/