org.beangle.commons.lang.time.InternetDateFormat.scala Maven / Gradle / Ivy

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/*
 * Copyright (C) 2005, The Beangle Software.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see .
 */

package org.beangle.commons.lang.time

import java.text.DecimalFormat
import java.util.*
import java.util.regex.Pattern

/** This object handles Internet date/time strings in accordance with RFC 3339. It
  * provides methods to convert from Calendar to RFC 3339 format strings and to parse these strings back into
  * the same constructs.
  * Strings are parsed in accordance with the RFC 3339 format:
  *
  *   * YYYY-MM-DD(T|t|\s)hh:mm:ss[.ddd][tzd]
  * 
  *
  * The tzd represents the time zone designator and is either an
  * upper or lower case 'Z' indicating UTC or a signed hh:mm offset.
  *
  * https://www.ietf.org/rfc/rfc3339.txt
  *
  * @see www.hackcraft.net/web/datetime
  */
private[time] object InternetDateFormat {

  val df2 = new DecimalFormat("00")
  val df3 = new DecimalFormat("000")
  val df4 = new DecimalFormat("0000")

  /** The Regex pattern to match. */
  val pattern = buildPattern()

  private def buildPattern(): Pattern = {
    val reDate = "(\\d{4})-(\\d{2})-(\\d{2})"
    val reTime = "(\\d{2}):(\\d{2}):(\\d{2})(\\.\\d+)?"
    val reZone = "(?:([zZ])|(?:(\\+|\\-)(\\d{2}):(\\d{2})))"
    val re = reDate + "[tT\\s]" + reTime + reZone;
    Pattern.compile(re)
  }

  /** Our private parse utility that parses the string, clears the calendar,
    * and then sets the fields.
    *
    * @param s   the string to parse
    * @param cal the calendar object to populate
    * @throws IllegalArgumentException
    * if the string is not a valid RFC 3339 date/time string
    */
  private def parse(s: String, cal: Calendar): Unit = {
    val m = pattern.matcher(s)
    if (!m.matches())
      throw new IllegalArgumentException("Invalid date/time: " + s);
    cal.clear()
    cal.set(Calendar.YEAR, Integer.parseInt(m.group(1)))
    cal.set(Calendar.MONTH, Integer.parseInt(m.group(2)) - 1)
    cal.set(Calendar.DAY_OF_MONTH, Integer.parseInt(m.group(3)))
    cal.set(Calendar.HOUR_OF_DAY, Integer.parseInt(m.group(4)))
    cal.set(Calendar.MINUTE, Integer.parseInt(m.group(5)))
    cal.set(Calendar.SECOND, Integer.parseInt(m.group(6)))
    if (m.group(7) != null) {
      val fraction = java.lang.Float.parseFloat(m.group(7))
      cal.set(Calendar.MILLISECOND, (fraction * 1000F).asInstanceOf[Int])
    }
    if (m.group(8) != null)
      cal.setTimeZone(new SimpleTimeZone(0, "Z"))
    else {
      val sign = if (m.group(9).equals("-")) -1 else 1
      val tzhour = Integer.parseInt(m.group(10))
      val tzminute = Integer.parseInt(m.group(11))
      val offset = sign * ((tzhour * 60) + tzminute)
      val id = Integer.toString(offset)
      cal.setTimeZone(new SimpleTimeZone(offset * 60000, id));
    }
  }

  /** Parses an RFC 3339 date/time string to a Calendar object.
    *
    * @param s the string to parse
    * @return the Calendar object
    * @throws IllegalArgumentException
    * if the string is not a valid RFC 3339 date/time string
    */
  def parse(s: String): Calendar = {
    val cal = new GregorianCalendar()
    parse(s, cal);
    cal
  }

  /** Converts the specified Calendar object to an RFC 3339 date/time string.
    * Unlike the toString methods for Date and long, no additional variant of
    * this method taking a time zone is provided since the time zone is built
    * into the Calendar object.
    *
    * @param cal the Calendar object
    * @return an RFC 3339 date/time string (does not include milliseconds)
    */
  def format(cal: Calendar): String = {
    val buf = new StringBuilder();
    buf.append(df4.format(cal.get(Calendar.YEAR)))
    buf.append("-")
    buf.append(df2.format(cal.get(Calendar.MONTH) + 1))
    buf.append("-")
    buf.append(df2.format(cal.get(Calendar.DAY_OF_MONTH)))
    buf.append("T")
    buf.append(df2.format(cal.get(Calendar.HOUR_OF_DAY)))
    buf.append(":")
    buf.append(df2.format(cal.get(Calendar.MINUTE)))
    buf.append(":")
    buf.append(df2.format(cal.get(Calendar.SECOND)))

    val ms = cal.get(Calendar.MILLISECOND)
    buf.append(".").append(df3.format(ms))

    var tzminute = (cal.get(Calendar.ZONE_OFFSET) + cal.get(Calendar.DST_OFFSET)) / 60000
    if (tzminute == 0)
      buf.append("Z")
    else {
      if (tzminute < 0) {
        tzminute = -tzminute
        buf.append("-")
      } else
        buf.append("+")
      val tzhour = tzminute / 60
      tzminute -= tzhour * 60
      buf.append(df2.format(tzhour))
      buf.append(":")
      buf.append(df2.format(tzminute));
    }
    buf.toString
  }

  /** Converts the specified Date object to an RFC 3339 date/time string using
    * the specified time zone.
    *
    * @param date the Date object
    * @param zone the time zone to use
    * @return an RFC 3339 date/time string (does not include milliseconds)
    */
  def format(date: Date, zone: TimeZone): String = {
    val cal = new GregorianCalendar(zone)
    cal.setTime(date)
    format(cal)
  }
}