69 lines
2.4 KiB
Java
69 lines
2.4 KiB
Java
/*
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* Copyright (c) 2007, 2023, 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 4944561
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* @summary Test hashCode() to have less than 10% of hash code conflicts.
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* @modules jdk.localedata
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* @run junit HashCodeTest
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*/
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import java.util.HashMap;
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import java.util.Locale;
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import java.util.Map;
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import org.junit.jupiter.api.Test;
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import static org.junit.jupiter.api.Assertions.assertFalse;
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public class HashCodeTest {
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// Ensure Locale.hashCode() has less than 10% conflicts
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@Test
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public void hashConflictsTest() {
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Locale[] locales = Locale.getAvailableLocales();
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int min = Integer.MAX_VALUE;
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int max = Integer.MIN_VALUE;
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Map<Integer, Locale> map = new HashMap<>(locales.length);
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int conflicts = 0;
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for (Locale loc : locales) {
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int hc = loc.hashCode();
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min = Math.min(hc, min);
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max = Math.max(hc, max);
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Integer key = hc;
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if (map.containsKey(key)) {
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conflicts++;
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System.out.println("conflict: " + map.get(key) + ", " + loc);
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} else {
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map.put(key, loc);
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}
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}
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System.out.println(locales.length + " locales: conflicts=" + conflicts
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+ ", min=" + min + ", max=" + max + ", diff=" + (max - min));
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assertFalse(conflicts >= (locales.length / 10),
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String.format("%s conflicts per %s locales", conflicts, locales.length));
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}
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}
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