Java example source code file (ConfigChanges.java)

This example Java source code file (ConfigChanges.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

cyclicbarrier, expected, fun, minutes, permissivesecuritymanger, random, runnable, seconds, security, some, threadfactory, threadgroup, threading, threadpoolexecutor, threads, throwable, throws, util

The ConfigChanges.java Java example source code

/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.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 {
    static final ThreadGroup tg = new ThreadGroup("pool");

    static final 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 abstract static 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);}}
}