1 /* 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 */ 22 23 /* 24 * This file is available under and governed by the GNU General Public 25 * License version 2 only, as published by the Free Software Foundation. 26 * However, the following notice accompanied the original version of this 27 * file: 28 * 29 * Written by Doug Lea with assistance from members of JCP JSR-166 30 * Expert Group and released to the public domain, as explained at 31 * http://creativecommons.org/publicdomain/zero/1.0/ 32 */ 33 34 /* 35 * @test 36 * @bug 8008378 37 * @summary Basic checks for parallelism 0, and null returning factory 38 * @run main/othervm -Djava.util.concurrent.ForkJoinPool.common.parallelism=0 ThreadLessCommon 39 * @run main/othervm -Djava.util.concurrent.ForkJoinPool.common.threadFactory=ThreadLessCommon$NullForkJoinWorkerThreadFactory ThreadLessCommon 40 * @author Chris Hegarty 41 */ 42 43 import java.util.concurrent.ForkJoinPool; 44 import java.util.concurrent.ForkJoinPool.ForkJoinWorkerThreadFactory; 45 import java.util.concurrent.ForkJoinWorkerThread; 46 import java.util.concurrent.RecursiveTask; 47 48 public class ThreadLessCommon { 49 50 static final int THRESHOLD = 1000; 51 static final boolean debug = true; 52 53 private static void realMain(String[] args) throws Throwable { 54 if (debug) { 55 String pp = System.getProperty( 56 "java.util.concurrent.ForkJoinPool.common.parallelism"); 57 System.out.println( 58 "java.util.concurrent.ForkJoinPool.common.parallelism:" + pp); 59 String tf = System.getProperty( 60 "java.util.concurrent.ForkJoinPool.common.threadFactory"); 61 System.out.println( 62 "java.util.concurrent.ForkJoinPool.common.threadFactory:" + tf); 63 } 64 65 long from = 0, to = 50000; 66 RecursiveTask<Long> task = new SumTask(from, to, Thread.currentThread()); 67 long sum = task.invoke(); 68 System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum); 69 70 task.fork(); 71 sum = task.join(); 72 System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum); 73 74 sum = ForkJoinPool.commonPool().invoke(task.fork()); 75 System.out.printf("%nSum: from [%d] to [%d] = [%d]%n", from, to, sum); 76 } 77 78 static class SumTask extends RecursiveTask<Long> { 79 final Thread expectedThread; 80 final long from; 81 final long to; 82 SumTask(long from, long to, Thread thread) { 83 this.from = from; this.to = to; expectedThread = thread; 84 } 85 86 @Override 87 public Long compute() { 88 check(Thread.currentThread() == expectedThread, 89 "Expected " + expectedThread + ", got " + Thread.currentThread()); 90 long range = to - from; 91 if (range < THRESHOLD) { 92 long acc = 0; 93 for (long i = from; i <= to; i++) 94 acc = acc + i; 95 return acc; 96 } else { 97 long half = from + range / 2; 98 SumTask t1 = new SumTask(from, half ,expectedThread); 99 SumTask t2 = new SumTask(half+1, to ,expectedThread); 100 if (half % 2 == 0) { 101 t1.fork(); 102 return t2.compute() + t1.join(); 103 } else { 104 invokeAll(t1, t2); 105 try { return t1.get() + t2.get(); } 106 catch (Exception x) { unexpected(x); return 0L;} 107 } 108 } 109 } 110 } 111 112 public static class NullForkJoinWorkerThreadFactory 113 implements ForkJoinWorkerThreadFactory 114 { 115 @Override 116 public ForkJoinWorkerThread newThread(ForkJoinPool pool) { 117 return null; 118 } 119 } 120 121 //--------------------- Infrastructure --------------------------- 122 static volatile int passed = 0, failed = 0; 123 static void pass() {passed++;} 124 static void fail() {failed++; /*Thread.dumpStack();*/} 125 static void fail(String msg) {System.out.println(msg); fail();} 126 static void unexpected(Throwable t) {failed++; t.printStackTrace();} 127 static void check(boolean cond, String msg) {if (cond) pass(); else fail(msg);} 128 static void equal(Object x, Object y) { 129 if (x == null ? y == null : x.equals(y)) pass(); 130 else fail(x + " not equal to " + y);} 131 public static void main(String[] args) throws Throwable { 132 try {realMain(args);} catch (Throwable t) {unexpected(t);} 133 System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); 134 if (failed > 0) throw new AssertionError("Some tests failed");} 135 }