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/* |
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* Copyright (c) 2018, Red Hat, Inc. All rights reserved. |
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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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import org.testng.annotations.Test; |
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|
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import java.lang.invoke.MethodHandle; |
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import java.lang.invoke.MethodHandles; |
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import java.lang.invoke.MethodType; |
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import java.lang.invoke.VarHandle; |
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import java.util.HashMap; |
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import java.util.Map; |
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import java.util.stream.IntStream; |
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|
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import static java.util.stream.Collectors.toMap; |
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import static org.testng.Assert.assertEquals; |
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import static org.testng.Assert.assertNull; |
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|
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/* |
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* @test |
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* @bug 8210280 |
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* @modules java.base/java.util:open |
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* @summary White box tests for HashMap internals around table resize |
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* @run testng WhiteBoxResizeTest |
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*/ |
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public class WhiteBoxResizeTest { |
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final MethodHandle TABLE_SIZE_FOR; |
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final VarHandle THRESHOLD; |
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final VarHandle TABLE; |
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|
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public WhiteBoxResizeTest() throws ReflectiveOperationException { |
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Class<?> mClass = HashMap.class; |
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String nodeClassName = mClass.getName() + "$Node"; |
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Class<?> nodeArrayClass = Class.forName("[L" + nodeClassName + ";"); |
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MethodHandles.Lookup lookup = MethodHandles.privateLookupIn(mClass, MethodHandles.lookup()); |
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TABLE = lookup.findVarHandle(mClass, "table", nodeArrayClass); |
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this.TABLE_SIZE_FOR = lookup.findStatic( |
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mClass, "tableSizeFor", |
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MethodType.methodType(int.class, int.class)); |
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this.THRESHOLD = lookup.findVarHandle(mClass, "threshold", int.class); |
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} |
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|
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int tableSizeFor(int n) { |
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try { |
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return (int) TABLE_SIZE_FOR.invoke(n); |
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} catch (Throwable t) { throw new AssertionError(t); } |
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} |
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|
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Object[] table(HashMap map) { |
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try { |
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return (Object[]) TABLE.get(map); |
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} catch (Throwable t) { throw new AssertionError(t); } |
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} |
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|
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int capacity(HashMap map) { |
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return table(map).length; |
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} |
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|
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@Test |
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public void testTableSizeFor() { |
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assertEquals(tableSizeFor(0), 1); |
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assertEquals(tableSizeFor(1), 1); |
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assertEquals(tableSizeFor(2), 2); |
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assertEquals(tableSizeFor(3), 4); |
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assertEquals(tableSizeFor(15), 16); |
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assertEquals(tableSizeFor(16), 16); |
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assertEquals(tableSizeFor(17), 32); |
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int maxSize = 1 << 30; |
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assertEquals(tableSizeFor(maxSize - 1), maxSize); |
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assertEquals(tableSizeFor(maxSize), maxSize); |
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assertEquals(tableSizeFor(maxSize + 1), maxSize); |
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assertEquals(tableSizeFor(Integer.MAX_VALUE), maxSize); |
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} |
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|
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@Test |
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public void capacityTest() { |
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HashMap<Integer, Integer> map = new HashMap<>(); |
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assertNull(table(map)); |
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|
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map.put(1, 1); |
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assertEquals(capacity(map), 16); |
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|
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map.putAll(IntStream.range(0, 64).boxed().collect(toMap(i -> i, i -> i))); |
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assertEquals(capacity(map), 128); |
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} |
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} |
