Java equivalent of Invariant Culture

Question

I am converting the following C# code to Java. Is there a Java equivalent to the .NET concept of Invariant Culture?

string upper = myString.ToUpperInvariant(); 

Since the Invariant Culture is really just the US culture, I could just do something like this in Java, but I'm wondering if there is a better way:

String upper = myString.toUpperCase(Locale.US); 

Answer 1

Update: Java 6 introduced Locale.ROOT which is described as:

This is regarded as the base locale of all locales, and is used as the language/country neutral locale for the locale sensitive operations.

This is probably better than using US, but I haven't checked it against the code below.

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No, that's basically the right way to go. While there are differences between the US culture and the invariant culture in terms of formatting, I don't believe they affect casing rules.

EDIT: Actually, a quick test program shows there are characters which are upper-cased differently in .NET in the US culture to in the invariant culture:

using System; using System.Globalization;  class Test {     static void Main()     {         CultureInfo us = new CultureInfo("en-US");         for (int i = 0; i < 65536; i++)         {             char c = (char) i;             string s = c.ToString();             if (s.ToUpperInvariant() != s.ToUpper(us))             {                 Console.WriteLine(i.ToString("x4"));             }         }     }     } 

Output:

00b5 0131 017f 01c5 01c8 01cb 01f2 0345 0390 03b0 03c2 03d0 03d1 03d5 03d6 03f0 03f1 03f5 1e9b 1fbe 

I don't have time to look at these right now, but it's worth investigating. I don't know if the same differences would apply in Java - you probably want to take a sample of them and work out what you want your code to do.

EDIT: And just to be completist, it's worth mentioning that that only checks for individual characters... whereas you're really upper-casing whole strings, which can make a difference.

Looking at the Java code for upper-casing, that appears to only have locale-specific behaviour for tr, az and lt countries. I know that tr is Turkey, but I don't know about the others...