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8200696: Optimal initial capacity of java.lang.Class.enumConstantDirectory

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Reviewed-by: dholmes, redestad
This commit is contained in:
Ivan Gerasimov 2018-04-04 14:09:31 -07:00
parent ceea439679
commit 277ac7e034
3 changed files with 141 additions and 4 deletions
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4
src/java.base/share/classes/java/lang/Class.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1994, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -3529,7 +3529,7 @@ public final class Class<T> implements java.io.Serializable,
if (universe == null)
throw new IllegalArgumentException(
getName() + " is not an enum type");
directory = new HashMap<>(2 * universe.length);
directory = new HashMap<>((int)(universe.length / 0.75f) + 1);
for (T constant : universe) {
directory.put(((Enum<?>)constant).name(), constant);
}

113
test/jdk/java/lang/Enum/ConstantDirectoryOptimalCapacity.java Normal file
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@ -0,0 +1,113 @@
/*
* Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* 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.
*/
/**
* @test
* @bug 8200696
* @summary Initial capacity of Class.enumConstantDirectory is not optimal
* @library /lib/testlibrary
* @modules java.base/java.lang:open
* @build jdk.testlibrary.OptimalCapacity
* @run main ConstantDirectoryOptimalCapacity
*/
import jdk.testlibrary.OptimalCapacity;
public class ConstantDirectoryOptimalCapacity {
public static void main(String[] args) throws Throwable {
test(E1.class);
test(E2.class);
test(E3.class);
test(E4.class);
test(E5.class);
test(E6.class);
test(E7.class);
test(E8.class);
test(E9.class);
test(E10.class);
test(E11.class);
test(E12.class);
test(E13.class);
test(E14.class);
test(E15.class);
test(E16.class);
test(E17.class);
test(E18.class);
test(E19.class);
test(E20.class);
test(E21.class);
test(E22.class);
test(E23.class);
test(E24.class);
test(E25.class);
test(E26.class);
}
private static void test(Class<? extends Enum> e) {
Enum.valueOf(e, "V0"); // trigger init of enumConstantDirectory
int initialCapacity = (int)(e.getEnumConstants().length / 0.75f) + 1;
OptimalCapacity.ofHashMap(e.getClass(), e, "enumConstantDirectory",
initialCapacity);
}
enum E1 { V0 }
enum E2 { V0, V1 }
enum E3 { V0, V1, V2 }
enum E4 { V0, V1, V2, V3 }
enum E5 { V0, V1, V2, V3, V4 }
enum E6 { V0, V1, V2, V3, V4, V5 }
enum E7 { V0, V1, V2, V3, V4, V5, V6 }
enum E8 { V0, V1, V2, V3, V4, V5, V6, V7 }
enum E9 { V0, V1, V2, V3, V4, V5, V6, V7, V8 }
enum E10 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9 }
enum E11 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10 }
enum E12 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11 }
enum E13 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12 }
enum E14 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13 }
enum E15 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14 }
enum E16 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15 }
enum E17 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16 }
enum E18 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17 }
enum E19 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18 }
enum E20 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18, V19 }
enum E21 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18, V19, V20 }
enum E22 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18, V19, V20, V21 }
enum E23 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18, V19, V20, V21, V22 }
enum E24 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18, V19, V20, V21, V22, V23 }
enum E25 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18, V19, V20, V21, V22, V23, V24 }
enum E26 { V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13,
V14, V15, V16, V17, V18, V19, V20, V21, V22, V23, V24, V25 }
}

28
test/jdk/lib/testlibrary/jdk/testlibrary/OptimalCapacity.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -101,11 +101,35 @@ public final class OptimalCapacity {
*/
public static void ofHashMap(Class<?> clazz, String fieldName,
int initialCapacity)
{
ofHashMap(clazz, null, fieldName, initialCapacity);
}
/**
* Checks adequacy of the initial capacity of a non-static field
* of type {@code HashMap}.
*
* Having
* <pre>
* class XClass {
* HashMap theMap = new HashMap(N);
* }
* XClass instance = ...
* </pre>
*
* you should call from the test
*
* <pre>
* OptimalCapacity.ofHashMap(XClass.class, instance, "theMap", N);
* </pre>
*/
public static void ofHashMap(Class<?> clazz, Object instance,
String fieldName, int initialCapacity)
{
try {
Field field = clazz.getDeclaredField(fieldName);
field.setAccessible(true);
Object obj = field.get(null);
Object obj = field.get(instance);
if (!HashMap.class.equals(obj.getClass())) {
throw new RuntimeException(field +
" expected to be of type HashMap");