code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.concurrent.ThreadPoolExecutor;
  
  /*
   * Copyright 2007 Sun Microsystems, Inc.  All Rights Reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
   * CA 95054 USA or visit www.sun.com if you need additional information or
   * have any questions.
   */
  
  /*
   * @test
   * @bug 6450200
   * @summary Test proper handling of pool state changes
   * @run main/othervm ConfigChanges
   * @author Martin Buchholz
   */
  
  import java.security.*;
  import java.util.*;
  import java.util.concurrent.*;
  import java.util.concurrent.atomic.*;
  import static java.util.concurrent.TimeUnit.*;
  
  public class ConfigChanges {
      final static ThreadGroup tg = new ThreadGroup("pool");
  
      final static Random rnd = new Random();
  
      static void report(ThreadPoolExecutor tpe) {
          try {
              System.out.printf(
                  "active=%d submitted=%d completed=%d queued=%d sizes=%d/%d/%d%n",
                  tg.activeCount(),
                  tpe.getTaskCount(),
                  tpe.getCompletedTaskCount(),
                  tpe.getQueue().size(),
                  tpe.getPoolSize(),
                  tpe.getCorePoolSize(),
                  tpe.getMaximumPoolSize());
          } catch (Throwable t) { unexpected(t); }
      }
  
      static void report(String label, ThreadPoolExecutor tpe) {
          System.out.printf("%10s ", label);
          report(tpe);
      }
  
      static class PermissiveSecurityManger extends SecurityManager {
          public void checkPermission(Permission p) { /* bien sur, Monsieur */ }
      }
  
      static void checkShutdown(final ExecutorService es) {
          final Runnable nop = new Runnable() {public void run() {}};
          try {
              if (new Random().nextBoolean()) {
                  check(es.isShutdown());
                  if (es instanceof ThreadPoolExecutor)
                      check(((ThreadPoolExecutor) es).isTerminating()
                            || es.isTerminated());
                  THROWS(RejectedExecutionException.class,
                         new Fun() {void f() {es.execute(nop);}});
              }
          } catch (Throwable t) { unexpected(t); }
      }
  
      static void checkTerminated(final ThreadPoolExecutor tpe) {
          try {
              checkShutdown(tpe);
              check(tpe.getQueue().isEmpty());
              check(tpe.isTerminated());
              check(! tpe.isTerminating());
              equal(tpe.getActiveCount(), 0);
              equal(tpe.getPoolSize(), 0);
              equal(tpe.getTaskCount(), tpe.getCompletedTaskCount());
              check(tpe.awaitTermination(0, SECONDS));
          } catch (Throwable t) { unexpected(t); }
      }
  
      static Runnable waiter(final CyclicBarrier barrier) {
          return new Runnable() { public void run() {
              try { barrier.await(); barrier.await(); }
              catch (Throwable t) { unexpected(t); }}};
      }
  
      static volatile Runnable runnableDuJour;
  
      private static void realMain(String[] args) throws Throwable {
          if (rnd.nextBoolean())
              System.setSecurityManager(new PermissiveSecurityManger());
  
          final boolean prestart = rnd.nextBoolean();
  
          final Thread.UncaughtExceptionHandler handler
              = new Thread.UncaughtExceptionHandler() {
                      public void uncaughtException(Thread t, Throwable e) {
                          check(! Thread.currentThread().isInterrupted());
                          unexpected(e);
                      }};
  
          final int n = 3;
          final ThreadPoolExecutor tpe
              = new ThreadPoolExecutor(n, 3*n,
                                       3L, MINUTES,
                                       new ArrayBlockingQueue<Runnable>(3*n));
          tpe.setThreadFactory(new ThreadFactory() {
                  public Thread newThread(Runnable r) {
                      Thread t = new Thread(tg, r);
                      t.setUncaughtExceptionHandler(handler);
                      return t;
                  }});
  
          if (prestart) {
              tpe.prestartAllCoreThreads();
              equal(tg.activeCount(), n);
              equal(tg.activeCount(), tpe.getCorePoolSize());
          }
  
          final Runnable runRunnableDuJour =
              new Runnable() { public void run() {
                  // Delay choice of action till last possible moment.
                  runnableDuJour.run(); }};
          final CyclicBarrier pumpedUp = new CyclicBarrier(3*n + 1);
          runnableDuJour = waiter(pumpedUp);
  
          if (prestart) {
              for (int i = 0; i < 1*n; i++)
                  tpe.execute(runRunnableDuJour);
              // Wait for prestarted threads to dequeue their initial tasks.
              while (! tpe.getQueue().isEmpty())
                  Thread.sleep(10);
              for (int i = 0; i < 5*n; i++)
                  tpe.execute(runRunnableDuJour);
          } else {
              for (int i = 0; i < 6*n; i++)
                  tpe.execute(runRunnableDuJour);
          }
  
          //report("submitted", tpe);
          pumpedUp.await();
          equal(tg.activeCount(), 3*n);
          equal(tg.activeCount(), tpe.getMaximumPoolSize());
          equal(tpe.getCorePoolSize(), n);
          //report("pumped up", tpe);
          equal(tpe.getMaximumPoolSize(), 3*n);
          tpe.setMaximumPoolSize(4*n);
          equal(tpe.getMaximumPoolSize(), 4*n);
          //report("pumped up2", tpe);
          final CyclicBarrier pumpedUp2 = new CyclicBarrier(n + 1);
          runnableDuJour = waiter(pumpedUp2);
          for (int i = 0; i < 1*n; i++)
              tpe.execute(runRunnableDuJour);
          pumpedUp2.await();
          equal(tg.activeCount(), 4*n);
          equal(tg.activeCount(), tpe.getMaximumPoolSize());
          equal(tpe.getCompletedTaskCount(), 0L);
          //report("pumped up2", tpe);
          runnableDuJour = new Runnable() { public void run() {}};
  
          tpe.setMaximumPoolSize(2*n);
          //report("after set", tpe);
  
          pumpedUp2.await();
          pumpedUp.await();
  
  //      while (tg.activeCount() != n &&
  //             tg.activeCount() != n)
  //          Thread.sleep(10);
  //      equal(tg.activeCount(), n);
  //      equal(tg.activeCount(), tpe.getCorePoolSize());
  
          while (tg.activeCount() != 2*n &&
                 tg.activeCount() != 2*n)
              Thread.sleep(10);
          equal(tg.activeCount(), 2*n);
          equal(tg.activeCount(), tpe.getMaximumPoolSize());
  
  
  //report("draining", tpe);
          while (tpe.getCompletedTaskCount() < 7*n &&
                 tpe.getCompletedTaskCount() < 7*n)
              Thread.sleep(10);
  
          //equal(tg.activeCount(), n);
          //equal(tg.activeCount(), tpe.getCorePoolSize());
          equal(tg.activeCount(), 2*n);
          equal(tg.activeCount(), tpe.getMaximumPoolSize());
  
          equal(tpe.getTaskCount(), 7L*n);
          equal(tpe.getCompletedTaskCount(), 7L*n);
  
          equal(tpe.getKeepAliveTime(MINUTES), 3L);
          tpe.setKeepAliveTime(7L, MILLISECONDS);
          equal(tpe.getKeepAliveTime(MILLISECONDS), 7L);
          while (tg.activeCount() > n &&
                 tg.activeCount() > n)
              Thread.sleep(10);
          equal(tg.activeCount(), n);
  
          //report("idle", tpe);
          check(! tpe.allowsCoreThreadTimeOut());
          tpe.allowCoreThreadTimeOut(true);
          check(tpe.allowsCoreThreadTimeOut());
          while (tg.activeCount() > 0 &&
                 tg.activeCount() > 0)
              Thread.sleep(10);
          equal(tg.activeCount(), 0);
  
          //report("idle", tpe);
  
          tpe.shutdown();
          checkShutdown(tpe);
          check(tpe.awaitTermination(3L, MINUTES));
          checkTerminated(tpe);
      }
  
      //--------------------- Infrastructure ---------------------------
      static volatile int passed = 0, failed = 0;
      static void pass() {passed++;}
      static void fail() {failed++; Thread.dumpStack();}
      static void fail(String msg) {System.out.println(msg); fail();}
      static void unexpected(Throwable t) {failed++; t.printStackTrace();}
      static void check(boolean cond) {if (cond) pass(); else fail();}
      static void equal(Object x, Object y) {
          if (x == null ? y == null : x.equals(y)) pass();
          else fail(x + " not equal to " + y);}
      public static void main(String[] args) throws Throwable {
          try {realMain(args);} catch (Throwable t) {unexpected(t);}
          System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
          if (failed > 0) throw new AssertionError("Some tests failed");}
      private static abstract class Fun {abstract void f() throws Throwable;}
      static void THROWS(Class<? extends Throwable> k, Fun... fs) {
          for (Fun f : fs)
              try { f.f(); fail("Expected " + k.getName() + " not thrown"); }
              catch (Throwable t) {
                  if (k.isAssignableFrom(t.getClass())) pass();
                  else unexpected(t);}}
  }
  