1 /* 2 * Copyright (c) 2012, 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 7121314 27 * @summary AbstractCollection.toArray(T[]) doesn't return the given array 28 * in concurrent modification. 29 * @author Ulf Zibis, David Holmes 30 */ 31 32 package test.java.util.AbstractCollection; 33 34 import java.util.AbstractCollection; 35 import java.util.Arrays; 36 import java.util.Iterator; 37 38 public class ToArrayTest { 39 40 static class TestCollection<E> extends AbstractCollection<E> { 41 private final E[] elements; 42 private int[] sizes; 43 private int nextSize; 44 TestCollection(E[] elements)45 public TestCollection(E[] elements) { 46 this.elements = elements; 47 setSizeSequence(new int[] { elements.length }); 48 } 49 50 /* 51 * Sets the values that size() will return on each use. The next 52 * call to size will return sizes[0], then sizes[1] etc. This allows us 53 * to emulate a concurrent change to the contents of the collection 54 * without having to perform concurrent changes. If sizes[n+1] contains 55 * a larger value, the collection will appear to have shrunk when 56 * iterated; if a smaller value then the collection will appear to have 57 * grown when iterated. 58 */ setSizeSequence(int... sizes)59 void setSizeSequence(int... sizes) { 60 this.sizes = sizes; 61 nextSize = 0; 62 } 63 64 /* can change collection's size after each invocation */ 65 @Override size()66 public int size() { 67 return sizes[nextSize == sizes.length - 1 ? nextSize : nextSize++]; 68 } 69 70 @Override iterator()71 public Iterator<E> iterator() { 72 return new Iterator<E>() { 73 int pos = 0; 74 75 public boolean hasNext() { 76 return pos < sizes[nextSize]; 77 } 78 public E next() { 79 return elements[pos++]; 80 } 81 public void remove() { 82 throw new UnsupportedOperationException( 83 "Not supported yet."); 84 } 85 }; 86 } 87 } 88 89 static final Object[] OBJECTS = { new Object(), new Object(), new Object() }; 90 static final TestCollection<?> CANDIDATE = new TestCollection<Object>(OBJECTS); 91 static final int CAP = OBJECTS.length; // capacity of the CANDIDATE 92 static final int LAST = CAP - 1; // last possible array index 93 Object[] a; 94 Object[] res; 95 last()96 int last() { 97 return a.length - 1; 98 } 99 test()100 protected void test() throws Throwable { 101 // Check array type conversion 102 res = new TestCollection<>(new Object[] { "1", "2" }).toArray(new String[0]); 103 check(res instanceof String[]); 104 check(res.length == 2); 105 check(res[1] == "2"); 106 107 // Check incompatible type of target array 108 try { 109 res = CANDIDATE.toArray(new String[CAP]); 110 check(false); 111 } catch (Throwable t) { 112 check(t instanceof ArrayStoreException); 113 } 114 115 // Check more elements than a.length 116 a = new Object[CAP - 1]; // appears too small 117 res = CANDIDATE.toArray(a); 118 check(res != a); 119 check(res[LAST] != null); 120 121 // Check equal elements as a.length 122 a = new Object[CAP]; // appears to match 123 res = CANDIDATE.toArray(a); 124 check(res == a); 125 check(res[last()] != null); 126 127 // Check equal elements as a.length 128 a = new Object[CAP + 1]; // appears too big 129 res = CANDIDATE.toArray(a); 130 check(res == a); 131 check(res[last()] == null); 132 133 // Check less elements than expected, but more than a.length 134 a = new Object[CAP - 2]; // appears too small 135 CANDIDATE.setSizeSequence(CAP, CAP - 1); 136 res = CANDIDATE.toArray(a); 137 check(res != a); 138 check(res.length == CAP - 1); 139 check(res[LAST - 1] != null); 140 141 // Check less elements than expected, but equal as a.length 142 a = Arrays.copyOf(OBJECTS, CAP); // appears to match 143 CANDIDATE.setSizeSequence(CAP, CAP - 1); 144 res = CANDIDATE.toArray(a); 145 check(res == a); 146 check(res[last()] == null); 147 148 // Check more elements than expected and more than a.length 149 a = new Object[CAP - 1]; // appears to match 150 CANDIDATE.setSizeSequence(CAP - 1, CAP); 151 res = CANDIDATE.toArray(a); 152 check(res != a); 153 check(res[LAST] != null); 154 155 // Check more elements than expected, but equal as a.length 156 a = new Object[CAP - 1]; // appears to match 157 CANDIDATE.setSizeSequence(CAP - 2, CAP - 1); 158 res = CANDIDATE.toArray(a); 159 check(res == a); 160 check(res[last()] != null); 161 162 // Check more elements than expected, but less than a.length 163 a = Arrays.copyOf(OBJECTS, CAP); // appears to match 164 CANDIDATE.setSizeSequence(CAP - 2, CAP - 1); 165 res = CANDIDATE.toArray(a); 166 check(res == a); 167 check(res[last()] == null); 168 169 test_7121314(); 170 } 171 172 /* 173 * Major target of this testcase, bug 7121314. 174 */ test_7121314()175 protected void test_7121314() throws Throwable { 176 // Check equal elements as a.length, but less than expected 177 a = new Object[CAP - 1]; // appears too small 178 CANDIDATE.setSizeSequence(CAP, CAP - 1); 179 res = CANDIDATE.toArray(a); 180 check(res == a); 181 check(res[last()] != null); 182 183 // Check less elements than a.length and less than expected 184 a = Arrays.copyOf(OBJECTS, CAP - 1); // appears too small 185 CANDIDATE.setSizeSequence(CAP, CAP - 2); 186 res = CANDIDATE.toArray(a); 187 check(res == a); 188 check(res[last()] == null); 189 190 } 191 main(String[] args)192 public static void main(String[] args) throws Throwable { 193 ToArrayTest testcase = new ToArrayTest(); 194 try { 195 testcase.test(); 196 } catch (Throwable t) { 197 unexpected(t); 198 } 199 200 System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); 201 if (failed > 0) throw new Exception("Some tests failed"); 202 } 203 204 //--------------------- Infrastructure --------------------------- 205 static volatile int passed = 0, failed = 0; pass()206 static void pass() { passed++; } fail()207 static void fail() { failed++; Thread.dumpStack(); } fail(String msg)208 static void fail(String msg) { System.out.println(msg); fail(); } unexpected(Throwable t)209 static void unexpected(Throwable t) { failed++; t.printStackTrace(); } check(boolean cond)210 static void check(boolean cond) { if (cond) pass(); else fail(); } equal(Object x, Object y)211 static void equal(Object x, Object y) { 212 if (x == null ? y == null : x.equals(y)) pass(); 213 else {System.out.println(x + " not equal to " + y); fail(); } 214 } 215 } 216