53a90d216f
HashMap bins with many collisions store entries in balanced trees Reviewed-by: alanb, dl, mduigou
94 lines
3.7 KiB
Java
94 lines
3.7 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 8005698
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* @summary Check operation of jdk.map.useRandomSeed property
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* @run main CheckRandomHashSeed
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* @run main/othervm -Djdk.map.useRandomSeed=false CheckRandomHashSeed
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* @run main/othervm -Djdk.map.useRandomSeed=bogus CheckRandomHashSeed
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* @run main/othervm -Djdk.map.useRandomSeed=true CheckRandomHashSeed true
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* @author Brent Christian
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*/
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import java.lang.reflect.Field;
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import java.util.Map;
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import java.util.HashMap;
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import java.util.LinkedHashMap;
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import java.util.Hashtable;
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import java.util.WeakHashMap;
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public class CheckRandomHashSeed {
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private final static String PROP_NAME = "jdk.map.useRandomSeed";
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static boolean expectRandom = false;
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public static void main(String[] args) {
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if (args.length > 0 && args[0].equals("true")) {
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expectRandom = true;
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}
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String hashSeedProp = System.getProperty(PROP_NAME);
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boolean propSet = (null != hashSeedProp)
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? Boolean.parseBoolean(hashSeedProp) : false;
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if (expectRandom != propSet) {
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throw new Error("Error in test setup: " + (expectRandom ? "" : "not " ) + "expecting random hashSeed, but " + PROP_NAME + " is " + (propSet ? "" : "not ") + "enabled");
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}
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testMap(new HashMap());
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testMap(new LinkedHashMap());
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testMap(new WeakHashMap());
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testMap(new Hashtable());
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}
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private static void testMap(Map map) {
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int hashSeed = getHashSeed(map);
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boolean hashSeedIsZero = (hashSeed == 0);
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if (expectRandom != hashSeedIsZero) {
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System.out.println("Test passed for " + map.getClass().getSimpleName() + " - expectRandom: " + expectRandom + ", hashSeed: " + hashSeed);
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} else {
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throw new Error ("Test FAILED for " + map.getClass().getSimpleName() + " - expectRandom: " + expectRandom + ", hashSeed: " + hashSeed);
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}
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}
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private static int getHashSeed(Map map) {
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try {
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if (map instanceof HashMap || map instanceof LinkedHashMap) {
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map.put("Key", "Value");
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Field hashSeedField = HashMap.class.getDeclaredField("hashSeed");
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hashSeedField.setAccessible(true);
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int hashSeed = hashSeedField.getInt(map);
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return hashSeed;
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} else {
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map.put("Key", "Value");
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Field hashSeedField = map.getClass().getDeclaredField("hashSeed");
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hashSeedField.setAccessible(true);
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int hashSeed = hashSeedField.getInt(map);
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return hashSeed;
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}
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} catch(Exception e) {
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e.printStackTrace();
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throw new Error(e);
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}
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}
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}
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