Joda LocalDateTime from LocalDate and string

Question

I have:

• a joda LocalDate, so it has no time information and just date
• a string which contains time and zone information, like "14:20 CEST"

Either of them can be absent (Scala's Option).

How can I combine these two to get joda LocalDateTime, i.e. entity representing only date and time with no timezone?

Answer 1

To combine these 2 options, the natural way is to use flatMap method like this:

val onlyDateOption: Option[LocalDate] = ???
val timeAndZoneOption: Option[String] = ???

val result: Option[LocalDateTime] = onlyDateOption.flatMap { onlyDate => 
  timeAndZoneOption.map { timeAndZone =>
    // Some logic here to build the LocalDateTime from onlyDate and timeAndZone
  }
}

Which can also be written with for-comprehension in more readible way:

val result: Option[LocalDateTime] =  for {
  onlyDate <- onlyDateOption
  timeAndZone <- timeAndZoneOption
} yield { 
  // Some logic here to build the LocalDateTime from onlyDate and timeAndZone
}

Now, how to use Joda to build what you're expecting can probably be done in various different ways, one could be:

onlyDate
  .toLocalDateTime(LocalTime.MIDNIGHT)
  .withHourOfDay(...) // hour extracted from the string somehow
  .withMinuteOfHour(...) // minute extracted from the string somehow

I'm not familiar with Joda API, there is probably another easier way