CODEWITHSUNDEEP
scala
VSe
VSe

Reputation: 929

get Current Date in Scala without java class

Is there any way to get the current date in Scala without using Java class import java.text.SimpleDateFormat and import java.util.Date?

Upvotes: 1

Views: 2293

Answers (3)

user unknown
user unknown

Reputation: 36260

Well, it's unclear - beside the hint about newer classes mentioned by Basil - why you would do this, need this.

On unix-like systems you can use the System date, probably on Windows systems too, but with the same syntax? You probably loose system independency: 

scala> import sys.process._
import sys.process._

scala> "date".!
Mi 31. Jan 07:09:04 CET 2018
res150: Int = 0

If you have a database, these often provide the date/time too.

Then you could try to get the date via TCP/IP.

All this solutions are in allmost all cases inferior to using the newer Java classes and even the older ones.

Upvotes: 0

Ryan Leach
Ryan Leach

Reputation: 4470

http://pavkin.ru/cross-platform-polymorphic-datetime-values-in-scala-with-type-classes/

The Goal There’s no solution without a goal. Precise goal will also provide correct context for reasonings in this article. So let me state it.

My primary goal is to be able to write cross-platform code that operates on date/time values with full time zone support.

This also means that I will need implementation(s) that behave consistently across JVM and browser. We’re Scala programmers, so let’s choose JVM behaviour semantics as our second goal.

Options explored in the article are

https://github.com/scala-js/scala-js-java-time

This library is the future of cross-platform date/time code. It’s effectively Java 8 time, written from scratch for ScalaJS.

At the time of writing this post, scala-js-java-time already provides LocalTime, LocalDate, Duration , and a handful of other really useful java.time.* classes (full list here).

https://github.com/soc/scala-java-time

Scala Java-Time is a fork of ThreeTen backport project. So it’s main purpose is to provide java.time.* -like functionality on Java 6 & 7.

It is also compiled to ScalaJS, which means we can write cross-platform code with it. And we can even use (to some extent) LocalDateTime!

https://github.com/mdedetrich/soda-time

Soda time is a port of Joda to ScalaJS.

It’s in early development stages and also doesn’t have time zones in ScalaJS, but I still added it to the list, because developers took an interesting approach: they are converting original Joda code with ScalaGen.

The author then goes to recommend that at the time of writing the article, (Published 11.11.2016)

There’s no cross-platform library with full time zone support. And for JavaScript runtime there’s only MomentJS, that really fits our requirements.

So unless one of those have evolved, or you only need a subset of datetime functions, or another solution has raised it's head, you are probably stuck implementing some sort of interface over the behavior needed, and swapping it out based on whether you are on java or scalajs.

Upvotes: 1

Basil Bourque
Basil Bourque

Reputation: 339561

java.time

You should not be importing java.text.SimpleDateFormat or java.util.Date. Those troublesome old classes are now legacy, supplanted by the java.time classes.

While I do not know Scala syntax, here is Java syntax.

java.time.Instant.now()  // Current moment in UTC, with a resolution of nanoseconds.

…and…

java.time.ZonedDateTime.now( ZoneId.of( "Africa/Tunis" ) )  // Current moment adjusted to the wall-clock time as used by the people in a particular region (time zone).

…and…

java.time.LocalDate.now( ZoneId.of( "Pacific/Auckland" ) )  // Current date (date-only, no time-of-day nor zone) of the people in a particular region (time zone).

Upvotes: 4

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