1 /* 2 * Copyright (c) 2005, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 /* 25 * @test 26 * @bug 6312056 4155650 4294891 4904074 27 * @summary Reasonable things should happen if mutating while iterating. 28 */ 29 30 import java.util.Iterator; 31 import java.util.Map; 32 import java.util.concurrent.ConcurrentHashMap; 33 import java.util.concurrent.ConcurrentMap; 34 import java.util.concurrent.ConcurrentSkipListMap; 35 36 public class ConcurrentModification { 37 static volatile int passed = 0, failed = 0; 38 39 static void fail(String msg) { 40 failed++; 41 new AssertionError(msg).printStackTrace(); 42 } 43 44 static void unexpected(Throwable t) { 45 failed++; 46 t.printStackTrace(); 47 } 48 49 static void check(boolean condition, String msg) { 50 if (condition) 51 passed++; 52 else 53 fail(msg); 54 } 55 56 static void check(boolean condition) { 57 check(condition, "Assertion failed"); 58 } 59 60 private static void test(ConcurrentMap<Integer, Integer> m) 61 { 62 try { 63 m.clear(); 64 check(m.isEmpty()); 65 m.put(1,2); 66 Iterator<Map.Entry<Integer,Integer>> it = m.entrySet().iterator(); 67 if (it.hasNext()) { 68 m.remove(1); // sneaky 69 Map.Entry<Integer, Integer> e = it.next(); 70 check(m.isEmpty()); 71 check(e.getKey() == 1); 72 check(e.getValue() == 2); 73 } 74 } catch (Throwable t) {unexpected(t);} 75 76 try { 77 m.clear(); 78 check(m.isEmpty()); 79 m.put(1,2); 80 Iterator<Map.Entry<Integer,Integer>> it = m.entrySet().iterator(); 81 if (it.hasNext()) { 82 m.put(1,3); // sneaky 83 Map.Entry<Integer, Integer> e = it.next(); 84 check(e.getKey() == 1); 85 check(e.getValue() == 2 || e.getValue() == 3); 86 if (m instanceof ConcurrentHashMap) { 87 e.setValue(4); 88 check(m.get(1) == 4); 89 } 90 } 91 } catch (Throwable t) {unexpected(t);} 92 } 93 94 public static void main(String[] args) { 95 test(new ConcurrentHashMap<Integer,Integer>()); 96 test(new ConcurrentSkipListMap<Integer,Integer>()); 97 98 System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); 99 if (failed > 0) throw new Error("Some tests failed"); 100 } 101 }