Guava: Provide a Converter<TimeUnit, ChronoUnit>

[kluever]

currently there's no official way (in JDK 8) for converting between java.util.concurrent.TimeUnit and ChronoUnit (there will be in JDK 9, though).

So we should consider providing one. Maybe it's time to start selectively open sourcing our com.google.common.time package?

[vharuty]

@kluever hi, please let me know what is the status for this issue, I would like to contribute.

[kluever]

There won't be any progress on this until we've completed the Guava for JDK8 transition.

[SimenB]

@kluever Is there a way to track that transition? Just the label?

[kluever]

We just made the transition to Java 8 internally last week, and we plan on releasing a Guava 21 (with Java8 support) sometime next quarter.

[SimenB]

Cool! Looking forward to it 😄

[Xaerxess]

Is it implemented internally? I'd really like to use the conversion with Guava 21.

[kluever]

I have a pending CL with this...I'll try to prioritize getting it API reviewed and released. Thanks for the bump.

[Xaerxess]

...or maybe in Guava 22? ;)

[kluever]

The reason we've been on the fence about adding this is that it already exists in threeten-extra as:

• Temporals.chronoUnit(TimeUnit)
• Temporals.timeUnit(ChronoUnit)

And we're hesitant to add competing solutions when a reasonable solution already exists.

[kevinb9n]

We've decided not to compete with threeten-extra.

[jbduncan]

@kevinb9n I think this would be good to note in the Ideas Graveyard, so that people are less likely to ask for this feature again in the future