91 lines
2.8 KiB
Java
91 lines
2.8 KiB
Java
/*
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* Copyright (c) 2014, 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 8046085
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* @summary Ensure that when trees are being used for collisions that null key
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* insertion still works.
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*/
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import java.util.*;
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import java.util.stream.IntStream;
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public class PutNullKey {
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// Initial capacity of map
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// Should be >= the map capacity for treeifying, see HashMap/ConcurrentMap.MIN_TREEIFY_CAPACITY
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static final int INITIAL_CAPACITY = 64;
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// Maximum size of map
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// Should be > the treeify threshold, see HashMap/ConcurrentMap.TREEIFY_THRESHOLD
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static final int SIZE = 256;
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// Load factor of map
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// A value 1.0 will ensure that a new threshold == capacity
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static final float LOAD_FACTOR = 1.0f;
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public static class CollidingHash implements Comparable<CollidingHash> {
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private final int value;
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public CollidingHash(int value) {
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this.value = value;
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}
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@Override
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public int hashCode() {
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// intentionally bad hashcode. Force into first bin.
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return 0;
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}
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@Override
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public boolean equals(Object o) {
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if (null == o) {
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return false;
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}
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if (o.getClass() != CollidingHash.class) {
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return false;
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}
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return value == ((CollidingHash) o).value;
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}
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@Override
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public int compareTo(CollidingHash o) {
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return value - o.value;
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}
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}
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public static void main(String[] args) throws Exception {
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Map<Object,Object> m = new HashMap<>(INITIAL_CAPACITY, LOAD_FACTOR);
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IntStream.range(0, SIZE)
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.mapToObj(CollidingHash::new)
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.forEach(e -> { m.put(e, e); });
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// kaboom?
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m.put(null, null);
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}
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}
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