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Lazily check for root, avoids unnecessary errors & resources

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Motivation:

io.netty.util.internal.PlatformDependent.isRoot() depends on the IS_ROOT field which is filled in during class initialization. This spawns processes and consumes resources, which are not generally necessary to the complete functioning of that class.

Modifications:

This switches the class to use lazy initialization this field inside of the isRoot() method using double-checked locking (http://en.wikipedia.org/wiki/Double-checked_locking).

Result:

The first call to isRoot() will be slightly slower, at a tradeoff that class loading is faster, uses fewer resources and platform errors are avoided unless necessary.
This commit is contained in:
Greg Gibeling 2014-11-25 09:28:10 -08:00 committed by Norman Maurer
parent c774b65f86
commit 66834bc818
1 changed files with 8 additions and 1 deletions
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9
common/src/main/java/io/netty/util/internal/PlatformDependent.java
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@ -60,7 +60,7 @@ public final class PlatformDependent {
private static final boolean IS_ANDROID = isAndroid0();
private static final boolean IS_WINDOWS = isWindows0();
private static final boolean IS_ROOT = isRoot0();
private static volatile Boolean IS_ROOT;
private static final int JAVA_VERSION = javaVersion0();
@ -114,6 +114,13 @@ public final class PlatformDependent {
* {@code false} if on Windows.
*/
public static boolean isRoot() {
if (IS_ROOT == null) {
synchronized (PlatformDependent.class) {
if (IS_ROOT == null) {
IS_ROOT = isRoot0();
}
}
}
return IS_ROOT;
}