PARQUET-430: Change to use Locale parameterized version of String.toUpperCase()/toLowerCase

[lw-lin]

A String is being converted to upper or lowercase, using the platform's default encoding. This may result in improper conversions when used with international characters.

For instance, "TITLE".toLowerCase() in a Turkish locale returns "tıtle", where 'ı' -- without a dot -- is the LATIN SMALL LETTER DOTLESS I character. To obtain correct results for locale insensitive strings, we'd better use toLowerCase(Locale.ENGLISH).

For more information on this, please see:

• http://stackoverflow.com/questions/11063102/using-locales-with-javas-tolowercase-and-touppercase
• http://lotusnotus.com/lotusnotus_en.nsf/dx/dotless-i-tolowercase-and-touppercase-functions-use-responsibly.htm
• http://java.sys-con.com/node/46241

This PR changes our use of String.toUpperCase()/toLowerCase() to String.toUpperCase(Locale.ENGLISH)/toLowerCase(Locale.ENGLISH)

[lw-lin]

@rdblue @liancheng Would you please take a look at this? Cheers.

[liancheng]

LGTM although I'm not quite sure whether it's absolutely necessary...

[lw-lin]

@liancheng
Some are not that necessary, but I think we'd better at least apply the following 3 changes:

• PrimitiveTypeName.valueOf(t.toUpperCase(Locale.ENGLISH))
• Repetition.valueOf(t.toUpperCase(Locale.ENGLISH))
• CompressionCodecName.toUpperCase(Locale.ENGLISH))

For instance, this code snippet reproduces an Exception when the default locale is tr:

String upper = "int32".toUpperCase(new Locale("tr"));
PrimitiveType.PrimitiveTypeName.valueOf(upper);

Exception is:

Exception in thread "main" java.lang.IllegalArgumentException: No enum constant org.apache.parquet.schema.PrimitiveType.PrimitiveTypeName.İNT32
at java.lang.Enum.valueOf(Enum.java:236)
at org.apache.parquet.schema.PrimitiveType$PrimitiveTypeName.valueOf(PrimitiveType.java:65)
at ...

Thanks.

[liancheng]

Agree, +1.

@rdblue Would you mind to also take a look?

[julienledem]

+1