util/HashMap/WhiteBoxResizeTest.java

/*
 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import org.testng.annotations.Test;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.invoke.VarHandle;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ThreadLocalRandom;
import java.util.function.Supplier;
import java.util.stream.IntStream;

import static java.util.stream.Collectors.toMap;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertNull;

/*
 * @test
 * @bug 8210280
 * @modules java.base/java.util:open
 * @summary White box tests for HashMap internals around table resize
 * @run testng WhiteBoxResizeTest
 * @key randomness
 */
public class WhiteBoxResizeTest {
    final ThreadLocalRandom rnd = ThreadLocalRandom.current();
    final MethodHandle TABLE_SIZE_FOR;
    final VarHandle THRESHOLD;
    final VarHandle TABLE;

    public WhiteBoxResizeTest() throws ReflectiveOperationException {
        Class<?> mClass = HashMap.class;
        String nodeClassName = mClass.getName() + "$Node";
        Class<?> nodeArrayClass = Class.forName("[L" + nodeClassName + ";");
        MethodHandles.Lookup lookup = MethodHandles.privateLookupIn(mClass, MethodHandles.lookup());
        TABLE = lookup.findVarHandle(mClass, "table", nodeArrayClass);
        this.TABLE_SIZE_FOR = lookup.findStatic(
                mClass, "tableSizeFor",
                MethodType.methodType(int.class, int.class));
        this.THRESHOLD = lookup.findVarHandle(mClass, "threshold", int.class);
    }

    int tableSizeFor(int n) {
        try {
            return (int) TABLE_SIZE_FOR.invoke(n);
        } catch (Throwable t) { throw new AssertionError(t); }
    }

    Object[] table(HashMap map) {
        try {
            return (Object[]) TABLE.get(map);
        } catch (Throwable t) { throw new AssertionError(t); }
    }

    int capacity(HashMap map) {
        return table(map).length;
    }

    @Test
    public void testTableSizeFor() {
        assertEquals(tableSizeFor(0), 1);
        assertEquals(tableSizeFor(1), 1);
        assertEquals(tableSizeFor(2), 2);
        assertEquals(tableSizeFor(3), 4);
        assertEquals(tableSizeFor(15), 16);
        assertEquals(tableSizeFor(16), 16);
        assertEquals(tableSizeFor(17), 32);
        int maxSize = 1 << 30;
        assertEquals(tableSizeFor(maxSize - 1), maxSize);
        assertEquals(tableSizeFor(maxSize), maxSize);
        assertEquals(tableSizeFor(maxSize + 1), maxSize);
        assertEquals(tableSizeFor(Integer.MAX_VALUE), maxSize);
    }

    @Test
    public void capacityTestDefaultConstructor() {
        capacityTestDefaultConstructor(new HashMap<>());
        capacityTestDefaultConstructor(new LinkedHashMap<>());
    }

    void capacityTestDefaultConstructor(HashMap<Integer, Integer> map) {
        assertNull(table(map));

        map.put(1, 1);
        assertEquals(capacity(map), 16); // default initial capacity

        map.putAll(IntStream.range(0, 64).boxed().collect(toMap(i -> i, i -> i)));
        assertEquals(capacity(map), 128);
    }

    @Test
    public void capacityTestInitialCapacity() {
        int initialCapacity = rnd.nextInt(2, 128);
        List<Supplier<HashMap<Integer, Integer>>> suppliers = List.of(
            () -> new HashMap<>(initialCapacity),
            () -> new HashMap<>(initialCapacity, 0.75f),
            () -> new LinkedHashMap<>(initialCapacity),
            () -> new LinkedHashMap<>(initialCapacity, 0.75f));

        for (Supplier<HashMap<Integer, Integer>> supplier : suppliers) {
            HashMap<Integer, Integer> map = supplier.get();
            assertNull(table(map));

            map.put(1, 1);
            assertEquals(capacity(map), tableSizeFor(initialCapacity));
        }
    }
}
Revision:	1.4
Committed:	Wed Dec 19 21:11:53 2018 UTC (5 years, 5 months ago) by jsr166
Branch:	MAIN
Changes since 1.3:	+1 -1 lines
Log Message:	capacityTestInitialCapacity avoid capacity of 1
#	User	Rev	Content
1	jsr166	1.1	/*
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	jsr166	1.2	import java.util.LinkedHashMap;
31			import java.util.List;
32	jsr166	1.1	import java.util.Map;
33	jsr166	1.2	import java.util.concurrent.ThreadLocalRandom;
34			import java.util.function.Supplier;
35	jsr166	1.1	import java.util.stream.IntStream;
36
37			import static java.util.stream.Collectors.toMap;
38			import static org.testng.Assert.assertEquals;
39			import static org.testng.Assert.assertNull;
40
41			/*
42			* @test
43			* @bug 8210280
44			* @modules java.base/java.util:open
45			* @summary White box tests for HashMap internals around table resize
46			* @run testng WhiteBoxResizeTest
47	jsr166	1.3	* @key randomness
48	jsr166	1.1	*/
49			public class WhiteBoxResizeTest {
50	jsr166	1.2	final ThreadLocalRandom rnd = ThreadLocalRandom.current();
51	jsr166	1.1	final MethodHandle TABLE_SIZE_FOR;
52			final VarHandle THRESHOLD;
53			final VarHandle TABLE;
54
55			public WhiteBoxResizeTest() throws ReflectiveOperationException {
56			Class<?> mClass = HashMap.class;
57			String nodeClassName = mClass.getName() + "$Node";
58			Class<?> nodeArrayClass = Class.forName("[L" + nodeClassName + ";");
59			MethodHandles.Lookup lookup = MethodHandles.privateLookupIn(mClass, MethodHandles.lookup());
60			TABLE = lookup.findVarHandle(mClass, "table", nodeArrayClass);
61			this.TABLE_SIZE_FOR = lookup.findStatic(
62			mClass, "tableSizeFor",
63			MethodType.methodType(int.class, int.class));
64			this.THRESHOLD = lookup.findVarHandle(mClass, "threshold", int.class);
65			}
66
67			int tableSizeFor(int n) {
68			try {
69			return (int) TABLE_SIZE_FOR.invoke(n);
70			} catch (Throwable t) { throw new AssertionError(t); }
71			}
72
73			Object[] table(HashMap map) {
74			try {
75			return (Object[]) TABLE.get(map);
76			} catch (Throwable t) { throw new AssertionError(t); }
77			}
78
79			int capacity(HashMap map) {
80			return table(map).length;
81			}
82
83			@Test
84			public void testTableSizeFor() {
85			assertEquals(tableSizeFor(0), 1);
86			assertEquals(tableSizeFor(1), 1);
87			assertEquals(tableSizeFor(2), 2);
88			assertEquals(tableSizeFor(3), 4);
89			assertEquals(tableSizeFor(15), 16);
90			assertEquals(tableSizeFor(16), 16);
91			assertEquals(tableSizeFor(17), 32);
92			int maxSize = 1 << 30;
93			assertEquals(tableSizeFor(maxSize - 1), maxSize);
94			assertEquals(tableSizeFor(maxSize), maxSize);
95			assertEquals(tableSizeFor(maxSize + 1), maxSize);
96			assertEquals(tableSizeFor(Integer.MAX_VALUE), maxSize);
97			}
98
99			@Test
100	jsr166	1.2	public void capacityTestDefaultConstructor() {
101			capacityTestDefaultConstructor(new HashMap<>());
102			capacityTestDefaultConstructor(new LinkedHashMap<>());
103			}
104
105			void capacityTestDefaultConstructor(HashMap<Integer, Integer> map) {
106	jsr166	1.1	assertNull(table(map));
107
108			map.put(1, 1);
109	jsr166	1.2	assertEquals(capacity(map), 16); // default initial capacity
110	jsr166	1.1
111			map.putAll(IntStream.range(0, 64).boxed().collect(toMap(i -> i, i -> i)));
112			assertEquals(capacity(map), 128);
113			}
114	jsr166	1.2
115			@Test
116			public void capacityTestInitialCapacity() {
117	jsr166	1.4	int initialCapacity = rnd.nextInt(2, 128);
118	jsr166	1.2	List<Supplier<HashMap<Integer, Integer>>> suppliers = List.of(
119			() -> new HashMap<>(initialCapacity),
120			() -> new HashMap<>(initialCapacity, 0.75f),
121			() -> new LinkedHashMap<>(initialCapacity),
122			() -> new LinkedHashMap<>(initialCapacity, 0.75f));
123
124			for (Supplier<HashMap<Integer, Integer>> supplier : suppliers) {
125			HashMap<Integer, Integer> map = supplier.get();
126			assertNull(table(map));
127
128			map.put(1, 1);
129			assertEquals(capacity(map), tableSizeFor(initialCapacity));
130			}
131			}
132	jsr166	1.1	}