1 /* 2 * Copyright (c) 2018, Red Hat, Inc. All rights reserved. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 */ 22 23 import org.testng.annotations.Test; 24 25 import java.lang.invoke.MethodHandle; 26 import java.lang.invoke.MethodHandles; 27 import java.lang.invoke.MethodType; 28 import java.lang.invoke.VarHandle; 29 import java.util.HashMap; 30 import java.util.Map; 31 import java.util.stream.IntStream; 32 33 import static java.util.stream.Collectors.toMap; 34 import static org.testng.Assert.assertEquals; 35 36 /* 37 * @test 38 * @bug 8210280 39 * @modules java.base/java.util:open 40 * @summary White box tests for HashMap internals around table resize 41 * @run testng WhiteBoxResizeTest 42 */ 43 public class WhiteBoxResizeTest { 44 final MethodHandle TABLE_SIZE_FOR; 45 final VarHandle THRESHOLD; 46 final VarHandle TABLE; 47 48 public WhiteBoxResizeTest() throws ReflectiveOperationException { 49 Class<?> mClass = HashMap.class; 50 String nodeClassName = mClass.getName() + "$Node"; 51 Class<?> nodeArrayClass = Class.forName("[L" + nodeClassName + ";"); 52 MethodHandles.Lookup lookup = MethodHandles.privateLookupIn(mClass, MethodHandles.lookup()); 53 TABLE = lookup.findVarHandle(mClass, "table", nodeArrayClass); 54 this.TABLE_SIZE_FOR = lookup.findStatic( 55 mClass, "tableSizeFor", 56 MethodType.methodType(int.class, int.class)); 57 this.THRESHOLD = lookup.findVarHandle(mClass, "threshold", int.class); 58 } 59 60 int tableSizeFor(int n) { 61 try { 62 return (int) TABLE_SIZE_FOR.invoke(n); 63 } catch (Throwable t) { throw new AssertionError(t); } 64 } 65 66 @Test 67 public void testTableSizeFor() { 68 assertEquals(tableSizeFor(0), 1); 69 assertEquals(tableSizeFor(1), 1); 70 assertEquals(tableSizeFor(2), 2); 71 assertEquals(tableSizeFor(3), 4); 72 assertEquals(tableSizeFor(15), 16); 73 assertEquals(tableSizeFor(16), 16); 74 assertEquals(tableSizeFor(17), 32); 75 int maxSize = 1 << 30; 76 assertEquals(tableSizeFor(maxSize - 1), maxSize); 77 assertEquals(tableSizeFor(maxSize), maxSize); 78 assertEquals(tableSizeFor(maxSize + 1), maxSize); 79 assertEquals(tableSizeFor(Integer.MAX_VALUE), maxSize); 80 } 81 82 @Test 83 public void putAllCapacityTest() { 84 var map = new HashMap<Integer, Integer>(); 85 map.put(1, 1); 86 map.putAll(IntStream.range(0, 64).boxed().collect(toMap(i -> i, i -> i))); 87 88 int capacity = ((Object[]) TABLE.get(map)).length; 89 assertEquals(capacity, 128); 90 } 91 }