[SPARK-13515] Make FormatNumber work irrespective of locale.

[lgieron]

What changes were proposed in this pull request?

Change in class FormatNumber to make it work irrespective of locale.

How was this patch tested?

Unit tests.

[srowen]

That looks good. Are there other instances where a DecimalFormat or NumberFormat doesn't specify a locale? we should fix anything of the same form.

[srowen]

Nit: this import should be grouped with the other java.text import.

[zsxwing]

I'm wondering if some people may want to use other Locale, such as 4.000. Why not just fix tests?

[lgieron]

@zsxwing This class is the backend for the format_number SQL function, which is supposed to be locale-independent.

[lgieron]

@srowen I went through all other uses of DecimalFormat and NumberFormat across all subprojects - they all look correct.

[zsxwing]

@lgieron I see.Thanks for clarifying.

[lgieron]

@srowen I've cleaned up the code as per your comments.

[srowen]

Nit: these should be grouped as java.text.{DecimalFormat, DecimalFormatSymbols}

[srowen]

Jenkins test this please

[SparkQA]

Test build #52122 has finished for PR 11396 at commit 40e1ec8.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[lgieron]

@srowen The build failed due to unrelated test failing (https://issues.apache.org/jira/browse/SPARK-13530). The fix was committed to master an hour ago and now the test passes.

[zsxwing]

ok to test

[SparkQA]

Test build #52144 has finished for PR 11396 at commit aab31f9.

• This patch fails Scala style tests.
• This patch merges cleanly.
• This patch adds no public classes.

[lgieron]

@zsxwing Can you please make Jenkins rerun the tests?

[SparkQA]

Test build #52145 has finished for PR 11396 at commit fef157f.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #52146 has finished for PR 11396 at commit b3b7b15.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

Looks good. CC @chenghao-intel to make sure we're not missing anything; I wasn't sure why there was a local DecimalFormat created in the first place. Is the non-thread-safety of the NumberFormat an issue here? I don't think so given my guess about how this is called, but thought I'd ask

[srowen]

Merged to master