| /* |
| * Copyright (c) 2004, 2013, 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 4486658 8010293 |
| * @summary thread safety of toArray methods of subCollections |
| * @author Martin Buchholz |
| */ |
| |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.stream.IntStream; |
| |
| public class ToArray { |
| |
| public static void main(String[] args) throws Throwable { |
| // Execute a number of times to increase the probability of |
| // failure if there is an issue |
| for (int i = 0; i < 16; i++) { |
| executeTest(); |
| } |
| } |
| |
| static void executeTest() throws Throwable { |
| final Throwable throwable[] = new Throwable[1]; |
| final ConcurrentHashMap<Integer, Integer> m = new ConcurrentHashMap<>(); |
| |
| // Number of workers equal to the number of processors |
| // Each worker will put globally unique keys into the map |
| final int nWorkers = Runtime.getRuntime().availableProcessors(); |
| final int sizePerWorker = 1024; |
| final int maxSize = nWorkers * sizePerWorker; |
| |
| // The foreman keeps checking that the size of the arrays |
| // obtained from the key and value sets is never less than the |
| // previously observed size and is never greater than the maximum size |
| // NOTE: these size constraints are not specific to toArray and are |
| // applicable to any form of traversal of the collection views |
| CompletableFuture<?> foreman = CompletableFuture.runAsync(new Runnable() { |
| private int prevSize = 0; |
| |
| private boolean checkProgress(Object[] a) { |
| int size = a.length; |
| if (size < prevSize) throw new RuntimeException("WRONG WAY"); |
| if (size > maxSize) throw new RuntimeException("OVERSHOOT"); |
| if (size == maxSize) return true; |
| prevSize = size; |
| return false; |
| } |
| |
| @Override |
| public void run() { |
| try { |
| Integer[] empty = new Integer[0]; |
| while (true) { |
| if (checkProgress(m.values().toArray())) return; |
| if (checkProgress(m.keySet().toArray())) return; |
| if (checkProgress(m.values().toArray(empty))) return; |
| if (checkProgress(m.keySet().toArray(empty))) return; |
| } |
| } |
| catch (Throwable t) { |
| throwable[0] = t; |
| } |
| } |
| }); |
| |
| // Create workers |
| // Each worker will put globally unique keys into the map |
| CompletableFuture<?>[] workers = IntStream.range(0, nWorkers). |
| mapToObj(w -> CompletableFuture.runAsync(() -> { |
| for (int i = 0, o = w * sizePerWorker; i < sizePerWorker; i++) |
| m.put(o + i, i); |
| })). |
| toArray(CompletableFuture<?>[]::new); |
| |
| // Wait for workers and then foreman to complete |
| CompletableFuture.allOf(workers).join(); |
| foreman.join(); |
| |
| if (throwable[0] != null) |
| throw throwable[0]; |
| } |
| } |