Consistency for function naming in Duration

[giwa]

toFormattedString should represent formatted millisecond like "10 ms" not simply give back "10"
toString should represent string of duration. It should simply give back string of millisecond.

Currently like this.

duration = Duration(10)
duration.toString()
>> "10 ms"
duration.toFormattedString()
>> "10"

Should be

duration = Duration(10)
duration.toString()
>> "10"
duration.toFormattedString()
>> "10 ms"

Please explain what does "formatted" mean? Why does it simply give millisecond with string?

[AmplabJenkins]

Can one of the admins verify this patch?

[ash211]

Where else in the Spark codebase are these methods called? If we're switching their meaning we need to make sure that callers are updated to expect the new formats.

[giwa]

@ash211 Thank you for your comment. After my second thought, this suggestion is not good. toString in Java world gives back human readable format.

The reason why I came up this question is I am writing wrapper of Duration in Python. Since you are familiar with Python, Could I ask some questions?

Do we need dunder str and dunder repr in Duration? If they are needed, what they should give back respectively?

str(Duration)
"10 ms"

repr(Duration)
"10"

BTW
toFormattedString is not used anywhere. Regarding to toString, I think it is not used anywhere in streaming, though I need more time to look deeply.

[ash211]

I'm familiar with the Python language but much less so the conventions like str vs repr.

From this SO post though, it looks like str should be "10 ms", but also repr should be something like "Duration(10ms)"

http://stackoverflow.com/questions/1436703/difference-between-str-and-repr-in-python