1 /* 2 * Copyright (c) 2011, 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 * Portions Copyright (c) 2011 IBM Corporation 26 */ 27 28 /* 29 * @test 30 * @bug 7014637 31 * @summary EnumSet's iterator.remove() can be resilient to set's modification. 32 * @author Neil Richards <neil.richards@ngmr.net>, <neil_richards@uk.ibm.com> 33 */ 34 package test.java.util.EnumSet; 35 36 import java.util.EnumSet; 37 import java.util.Iterator; 38 import java.util.Set; 39 40 public class SmallEnumIteratorRemoveResilience { 41 // enum with less than 64 values 42 private static enum SmallEnum { e0, e1, e2 } 43 main(final String[] args)44 public static void main(final String[] args) throws Exception { 45 final Set<SmallEnum> set = EnumSet.noneOf(SmallEnum.class); 46 47 set.add(SmallEnum.e0); 48 set.add(SmallEnum.e1); 49 50 final Iterator<SmallEnum> iterator = set.iterator(); 51 52 int size = set.size(); 53 SmallEnum element = iterator.next(); 54 55 iterator.remove(); 56 checkSetAfterRemoval(set, size, element); 57 58 size = set.size(); 59 element = iterator.next(); 60 61 set.remove(element); 62 checkSetAfterRemoval(set, size, element); 63 64 // The Java API declares that the behaviour here - to call 65 // iterator.remove() after the underlying collection has been 66 // modified - is "unspecified". 67 // However, in the case of iterators for EnumSet, it is easy to 68 // implement their remove() operation such that the set is 69 // unmodified if it is called for an element that has already been 70 // removed from the set - this being the naturally "resilient" 71 // behaviour. 72 iterator.remove(); 73 checkSetAfterRemoval(set, size, element); 74 } 75 checkSetAfterRemoval(final Set<SmallEnum> set, final int origSize, final SmallEnum removedElement)76 private static void checkSetAfterRemoval(final Set<SmallEnum> set, 77 final int origSize, final SmallEnum removedElement) 78 throws Exception { 79 if (set.size() != (origSize - 1)) { 80 throw new Exception("Test FAILED: Unexpected set size after removal; expected '" + (origSize - 1) + "' but found '" + set.size() + "'"); 81 } 82 if (set.contains(removedElement)) { 83 throw new Exception("Test FAILED: Element returned from iterator unexpectedly still in set after removal."); 84 } 85 } 86 } 87