Skip to content
Permalink
Browse files
8263090: Avoid reading volatile fields twice in Locale.getDefault(Cat…
…egory)

Reviewed-by: rriggs, naoto, serb
  • Loading branch information
cl4es committed Mar 8, 2021
1 parent 61cff4d commit 13625bebd035f26616211176b3abc4105eeb660d
Show file tree
Hide file tree
Showing 2 changed files with 87 additions and 20 deletions.
@@ -939,29 +939,38 @@ public static Locale getDefault() {
*/
public static Locale getDefault(Locale.Category category) {
// do not synchronize this method - see 4071298
switch (category) {
case DISPLAY:
if (defaultDisplayLocale == null) {
synchronized(Locale.class) {
if (defaultDisplayLocale == null) {
defaultDisplayLocale = initDefault(category);
}
}
Objects.requireNonNull(category);
if (category == Category.DISPLAY) {
Locale loc = defaultDisplayLocale; // volatile read
if (loc == null) {
loc = getDisplayLocale();
}
return defaultDisplayLocale;
case FORMAT:
if (defaultFormatLocale == null) {
synchronized(Locale.class) {
if (defaultFormatLocale == null) {
defaultFormatLocale = initDefault(category);
}
}
return loc;
} else {
assert category == Category.FORMAT : "Unknown category";
Locale loc = defaultFormatLocale; // volatile read
if (loc == null) {
loc = getFormatLocale();
}
return defaultFormatLocale;
default:
assert false: "Unknown Category";
return loc;
}
}

private static synchronized Locale getDisplayLocale() {
Locale loc = defaultDisplayLocale;
if (loc == null) {
loc = defaultDisplayLocale = initDefault(Category.DISPLAY);
}
return loc;
}


private static synchronized Locale getFormatLocale() {
Locale loc = defaultFormatLocale;
if (loc == null) {
loc = defaultFormatLocale = initDefault(Category.FORMAT);
}
return getDefault();
return loc;
}

private static Locale initDefault() {
@@ -0,0 +1,58 @@
/*
* Copyright (c) 2021, 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.
*/
package org.openjdk.bench.java.util;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;

import java.util.Locale;
import java.util.concurrent.TimeUnit;

/*
* This benchmark tests Locale.getDefault variants
*/
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Benchmark)
public class LocaleDefaults {

@Benchmark
public Locale getDefault() {
return Locale.getDefault();
}

@Benchmark
public Locale getDefaultDisplay() {
return Locale.getDefault(Locale.Category.DISPLAY);
}

@Benchmark
public Locale getDefaultFormat() {
return Locale.getDefault(Locale.Category.FORMAT);
}
}

0 comments on commit 13625be

Please sign in to comment.