// 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]
*/