Proper deserialisation of Java 8 Time

ISO8601-json.scala

  /**
   * Java 8 does not full support ISO8601 date/time format. (https://en.m.wikipedia.org/wiki/ISO_8601)
   * It does not support timezone '±HHMM' or '±HH'.
   * This has been reported in issue https://bugs.openjdk.java.net/browse/JDK-8032051,
   * but has only been fixed in Java 9, not in Java 8!
   *
   * This object provides an alternative [[Reads]] instance which fully supports ISO8601 formats,
   * which should be used instead of Play Json's [[play.api.libs.json.EnvReads.DefaultInstantReads]].
   */
  object ISO8601 {
    import java.time.format.{ DateTimeFormatter, DateTimeFormatterBuilder }

    // formatter for timezone ±[hh][mm]
    private val ISO8601_ALT1 = new DateTimeFormatterBuilder()
      .parseCaseInsensitive()
      .append(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
      .appendOffset("+HHMM", "Z")
      .toFormatter()
    // formatter for timezone ±[hh]
    private val ISO8601_ALT2 = new DateTimeFormatterBuilder()
      .parseCaseInsensitive()
      .append(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
      .appendOffset("+HH", "Z")
      .toFormatter()

    val InstantReads =
      Reads.DefaultInstantReads orElse // default formatter only partially supports ISO8601. See https://bugs.openjdk.java.net/browse/JDK-8032051
        Reads.instantReads(ISO8601_ALT1) orElse
        Reads.instantReads(ISO8601_ALT2)

  }