102 lines
3.8 KiB
Java
102 lines
3.8 KiB
Java
/*
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* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* @test
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* @bug 8025173
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* @summary Verify that replacing the value for an existing key does not
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* corrupt active iterators, in particular due to a resize() occurring and
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* not updating modCount.
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* @run main ReplaceExisting
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*/
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import java.util.ConcurrentModificationException;
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import java.util.HashMap;
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import java.util.HashSet;
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import java.util.Iterator;
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public class ReplaceExisting {
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/* Number of entries required to trigger a resize for cap=16, load=0.75*/
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private static int ENTRIES = 13;
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public static void main(String[] args) {
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for (int i = 0; i <= ENTRIES; i++) {
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HashMap<Integer,Integer> hm = prepHashMap();
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testItr(hm, i);
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}
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}
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/* Prepare a HashMap that will resize on next put() */
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private static HashMap<Integer,Integer> prepHashMap() {
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HashMap<Integer,Integer> hm = new HashMap<>(16, 0.75f);
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// Add items to one more than the resize threshold
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for (int i = 0; i < ENTRIES; i++) {
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hm.put(i*10, i*10);
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}
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return hm;
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}
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/* Iterate hm for elemBeforePut elements, then call put() to replace value
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* for existing key. With bug 8025173, this will also cause a resize, but
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* not increase the modCount.
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* Finish the iteration to check for a corrupt iterator.
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*/
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private static void testItr(HashMap<Integer,Integer> hm, int elemBeforePut) {
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if (elemBeforePut > hm.size()) {
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throw new IllegalArgumentException("Error in test: elemBeforePut must be <= HashMap size");
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}
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// Create a copy of the keys
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HashSet<Integer> keys = new HashSet<>(hm.size());
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keys.addAll(hm.keySet());
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HashSet<Integer> collected = new HashSet<>(hm.size());
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// Run itr for elemBeforePut items, collecting returned elems
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Iterator<Integer> itr = hm.keySet().iterator();
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for (int i = 0; i < elemBeforePut; i++) {
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Integer retVal = itr.next();
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if (!collected.add(retVal)) {
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throw new RuntimeException("Corrupt iterator: key " + retVal + " already encountered");
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}
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}
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// Do put() to replace entry (and resize table when bug present)
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if (null == hm.put(0, 100)) {
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throw new RuntimeException("Error in test: expected key 0 to be in the HashMap");
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}
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// Finish itr + collecting returned elems
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while(itr.hasNext()) {
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Integer retVal = itr.next();
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if (!collected.add(retVal)) {
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throw new RuntimeException("Corrupt iterator: key " + retVal + " already encountered");
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}
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}
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// Compare returned elems to original copy of keys
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if (!keys.equals(collected)) {
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throw new RuntimeException("Collected keys do not match original set of keys");
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}
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}
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}
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