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/*
* 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.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
/*
* @test
* @bug 8008378
* @summary Basic checks for parallelism 0, and null returning factory
* @run main/othervm -Djava.util.concurrent.ForkJoinPool.common.parallelism=0 ThreadLessCommon
* @run main/othervm -Djava.util.concurrent.ForkJoinPool.common.threadFactory=ThreadLessCommon$NullForkJoinWorkerThreadFactory ThreadLessCommon
* @author Chris Hegarty
*/
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinPool.ForkJoinWorkerThreadFactory;
import java.util.concurrent.ForkJoinWorkerThread;
import java.util.concurrent.RecursiveTask;
public class ThreadLessCommon {
static final int THRESHOLD = 1000;
static final boolean debug = true;
private static void realMain(String[] args) throws Throwable {
if (debug) {
String pp = System.getProperty(
"java.util.concurrent.ForkJoinPool.common.parallelism");
System.out.println(
"java.util.concurrent.ForkJoinPool.common.parallelism:" + pp);
String tf = System.getProperty(
"java.util.concurrent.ForkJoinPool.common.threadFactory");
System.out.println(
"java.util.concurrent.ForkJoinPool.common.threadFactory:" + tf);
}
long from = 0, to = 50000;
RecursiveTask<Long> task = new SumTask(from, to, Thread.currentThread());
long sum = task.invoke();
System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum);
task.fork();
sum = task.join();
System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum);
sum = ForkJoinPool.commonPool().invoke(task.fork());
System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum);
}
static class SumTask extends RecursiveTask<Long> {
final Thread expectedThread;
final long from;
final long to;
SumTask(long from, long to, Thread thread) {
this.from = from; this.to = to; expectedThread = thread;
}
@Override
public Long compute() {
check(Thread.currentThread() == expectedThread,
"Expected " + expectedThread + ", got " + Thread.currentThread());
long range = to - from;
if (range < THRESHOLD) {
long acc = 0;
for (long i = from; i <= to; i++)
acc = acc + i;
return acc;
} else {
long half = from + range / 2;
SumTask t1 = new SumTask(from, half ,expectedThread);
SumTask t2 = new SumTask(half+1, to ,expectedThread);
if (half % 2 == 0) {
t1.fork();
return t2.compute() + t1.join();
} else {
invokeAll(t1, t2);
try { return t1.get() + t2.get(); }
catch (Exception x) { unexpected(x); return 0L;}
}
}
}
}
public static class NullForkJoinWorkerThreadFactory
implements ForkJoinWorkerThreadFactory
{
@Override
public ForkJoinWorkerThread newThread(ForkJoinPool pool) {
return null;
}
}
//--------------------- 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, String msg) {if (cond) pass(); else fail(msg);}
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");}
}
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