Consider migrating joda-time to `java.time`

[richardstartin]

Joda-time was superseded by java.time when JDK8 was released and there is a straightforward migration path.

[ddcprg]

@richardstartin @xiangfu0 I might be able to look into this one if no one else has picked it up

[richardstartin]

@ddcprg that would be awesome! As part of the effort, I would suggest building some unit testing around DateTimeFunctions to be sure there aren't any regressions.

There is a blog post from the author of both libraries on performing the migration (from 2014) here. Don't miss the comment here:

One more "odds and ends" which is important to be aware of:

the Joda DateTimeFormat (http://www.joda.org/joda-time/apidocs/org/joda/time/format/DateTimeFormat.html) uses "Y" for "year of era", and "y" for "year". The Java 8 DateTimeFormatter (https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html) uses "Y" for "week based year", and "y" for "year of era". If you're currently using a Joda DateTimeFormat object with "Y" as part of the pattern, this may introduce an off-by-one error (https://stackoverflow.com/questions/26431882/difference-between-year-of-era-and-week-based-year) if you change it to a Java 8 DateTimeFormatter without also replacing "Y" with "y" in the pattern string.

[ddcprg]

Cool, Thank you for the suggestions!

[ddcprg]

Looks like this is going to be a large piece of work. I've opened a draft PR with unit tests for the scalar functions, more to come

[camac]

Looks like this is going to be a large piece of work. I've opened a draft PR with unit tests for the scalar functions, more to come

Hi @ddcprg Happy to help make this migration easier. I am currently working on an IntelliJ plugin called Sensei that provides custom recipes/rules that can help migrate and rewrite code as defined. I have a bunch of rules created for Joda to Java-Time migration and would love to contribute if they would help this process. Would you be interested?

[ddcprg]

hey @camac that'd be great!

[camac]

@ddcprg Excellent! we are hoping to publish these Joda-Time to java.time migration recipes tomorrow. After they are published I can give you a demo on how to use them? I'm in Sydney, Australia so if the time zone doesn't suit I can do a blog post / video demonstrating how to use Sensei and these recipes to perform a large part of the migration.

[ddcprg]

@camac many thanks, indeed it may be difficult to schedule a time for a live demo. It may be better a blog post / video so everyone else can also look at it if they are interested. Cheers!

[camac]

@ddcprg no worries! I'm working on the blog post this week. I'll post here when it's published