Java Thread - 如何使用ReentrantLock...

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

public class Main {
  public static void main(final String[] args) throws Exception {
    Random RND = new Random();
    ExecutorService es = Executors.newFixedThreadPool(Runtime.getRuntime()
        .availableProcessors());
    List<Future<String>> results = new ArrayList<>(10);
    for (int i = 0; i < 10; i++) {
      results
          .add(es.submit(new TimeSliceTask(RND.nextInt(10), TimeUnit.SECONDS)));
    }
    es.shutdown();
    while (!results.isEmpty()) {
      Iterator<Future<String>> i = results.iterator();
      while (i.hasNext()) {
        Future<String> f = i.next();
        if (f.isDone()) {
          System.out.println(f.get());
          i.remove();
        }
      }
    }
  }
}

class TimeSliceTask implements Callable<String> {
  long timeToLive;
  long duration;
  public TimeSliceTask(final long timeToLive, final TimeUnit timeUnit) {
    this.timeToLive = System.nanoTime() + timeUnit.toNanos(timeToLive);
    this.duration = timeUnit.toMillis(timeToLive);
  }

  @Override
  public String call() throws Exception {
    while (timeToLive <= System.nanoTime()) {
      // simulate work here
      Thread.sleep(500);
    }
    final long end = System.nanoTime();
    return String.format("Finished Elapsed Time = %d, scheduled for %d",
        TimeUnit.NANOSECONDS.toMillis(timeToLive - end), this.duration);
  }
}