Strongly Typed Time for Scala.
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README.md

arallon

Strongly Typed Time for Scala.

Build Status

See

Installation

Bring in the library by adding the following to your build.sbt.

  • The release repository:
   resolvers ++= Seq(
     "Millhouse Bintray"  at "http://dl.bintray.com/themillhousegroup/maven"
   )
  • The dependency itself:
   libraryDependencies ++= Seq(
     "com.themillhousegroup" %% "arallon" % "0.1.45"
   )

Usage

Once you have arallon added to your project, you can start using it like this:

import com.themillhousegroup.arallon._
import com.themillhousegroup.arallon.zones._
Get a strongly-typed representation of "now":
val nowInParis = TimeInZone[Paris]
// TimeInZone[Paris] UTC: '2015-05-10T03:04:15.876Z' Local: '2015-05-10T05:04:15.876+02:00'
Get a TimeInZone[TZ] in lots of other ways:
val fromAJavaTimeZoneString:TimeInZone[TimeZone] = TimeInZone.now("Europe/Paris")

val now:TimeInZone[UTC] = TimeInZone.nowUTC

val fromMillis:TimeInZone[UTC] = TimeInZone.fromUTCMillis(123456789)

val fromMillisInTimeZone:TimeInZone[TimeZone] = TimeInZone.fromMillis(123456789, "Europe/Paris")

val fromADateTime:TimeInZone[Berlin] = TimeInZone.fromUTCTo[Berlin](aJodaDateTimeInUTC)

val fromADateTimeToUTC:TimeInZone[UTC] = TimeInZone.fromUTC(aJodaDateTimeInUTC)

val fromADateTime:TimeInZone[Berlin] = TimeInZone[Berlin](aBerlinJodaDateTime)

val inNamedZone:TimeInZone[TimeZone] = TimeInZone("America/New_York", aNewYorkJodaDateTime)
Transform the time, while remaining in the same time zone:
val threePMParisConferenceCall = nowInParis.transform(_.withTime(15,0,0,0))
// TimeInZone[Paris] UTC: '2015-05-10T13:00:00.000Z' Local: '2015-05-10T15:00:00.000+02:00
Map an instant to another time zone:
val wakeUpCall = threePMParisConferenceCall.map[Sydney]
// TimeInZone[Sydney] UTC: '2015-05-10T13:00:00.000Z' Local: '2015-05-10T23:00:00.000+10:00'

Notice how performing the map to Sydney-time didn't change the instant being referred to - which is what you want if you're trying to join a conference call starting at that instant.

If you're looking for something client-side to generate a nice IANA string (like Europe/Paris) take a look at jstimezonedetect on GitHub - pass that to your Scala server-side and you can be strongly-typed from then on.

Serialize / Deserialize TimeInZone instances:
import com.themillhousegroup.arallon.traits.TimeInZoneSerializing


val t = TimeInZone[Paris]

val s = t.serialize(t) 

// Gives: "435363632Z:Europe/Paris"

val t2:TimeInZone[TimeZone] = TimeInZoneSerializing.deserialize(s) 

Credits

  • The fantastic Joda-Time does all the heavy lifting

Arallon?

The project is named after a fictional island in Episode 6 of the first season of HBO's Silicon Valley. The island was being built directly on the International Date Line - half in one timezone (and hence day), half in the other.

The name appealed for a couple of reasons - firstly, dealing with time on such an island would be hugely annoying and error-prone. Secondly, the construction of the island itself was fully automated using robotics and computers - no humans were involved.

The aim of this project is to approach that level of automation, where the compiler ensures that errors don't occur when working with timezones.