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  1. JDK
  2. JDK-8047872

Need more rigorous way to get locale-specific Date and Time formats

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Details

    • Enhancement
    • Resolution: Duplicate
    • P4
    • None
    • 7u55
    • core-libs
    • x86
    • windows_7

    Description

      A DESCRIPTION OF THE REQUEST :
      I need a way to get a Time format pattern that reliably includes seconds, and another that includes milliseconds, for any locale. Right now, I can specify the FULL for the time format, and for some Locales I get seconds, but for others, I don't. And there is no way to ask for a formatter that includes milliseconds.

      JUSTIFICATION :
      My business requirements call for a two ways to express a Time value, formatted for the default Locale. I need one way that includes seconds, and another that includes milliseconds. But there is no way to get this information from the getDateTimeInstance() or getTimeInstance() methods. This means I need to add special code to insert a seconds field into the pattern if it's missing. If I need milliseconds, I need to do the same for that field, too, but I also need to figure out what the decimal character is for the Locale. This code gets hairy, and it defeats the purpose of letting me ask for a formatter for a specific Locale.

      Locales are very useful for proving the proper syntax, but I don't want them deciding which fields to include, because that's determined by my business requirements, not by the local custom.



      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      I would like a way to ask for a formatter that lets me say if I need seconds, or milliseconds. For example, a third parameter could be added where a new constant specifies the precision:

      DateFormat fmt = DateFormat.getTimeInstance(DateFormat.FULL, locale, PRECISION_SECONDS);
      DateFormat fmt2 = DateFormat.getTimeInstance(DateFormat.FULL, locale, PRECISION_MILLISECONDS);

      Alternatively, new methods could serve to address this:

      DateFormat fmt = DateFormat.getTimeInstanceWithSeconds(locale);
      DateFormat fmt2 = DateFormat.getTimeInstanceWithMillis(locale);

      These methods would return a formatter that inlcudes fields of the specified precision, regardless of the specified style.

      ACTUAL -
      Calling getTimeInstance(DateFormat.FULL, locale) will usually return a format with seconds, but some locales don't. (sv_SE, it_CH, de_*, pt_PT, for example.) None of the methods return a time that includes milliseconds.

      ---------- BEGIN SOURCE ----------
      /*
       * Copyright (C) 2014, Cast & Crew (R) Software, LLC
       * All rights reserved. Unauthorized disclosure or distribution is prohibited.
       */
      package com.fun;

      import java.text.DateFormat;
      import java.text.ParseException;
      import java.text.SimpleDateFormat;
      import java.util.Date;
      import java.util.Locale;

      /**
       * DateFormatTest
       * <p/>
       * Lines beginning with a * do not include a field for seconds.
       *
       * @author <a href="mailto:miguel.munoz@castandcrew.com">Miguel Mu\u00f1oz</a>
       */
      public final class DateFormatTest {
          private DateFormatTest() { }


          // ------------------------------------------------------------------------------------------------- //
          // Only used by internal main() method.

          public static void main(final String[] args) throws ParseException {
              Locale[] allLocales = Locale.getAvailableLocales();
              java.util.Comparator<Locale> comparator = new java.util.Comparator<Locale>() {
                  @Override
                  public int compare(final Locale o1, final Locale o2) {
                      int returnValue = o1.getLanguage().compareTo(o2.getLanguage());
                      if (returnValue == 0) {
                          returnValue = o1.getCountry().compareTo(o2.getCountry());
                          if (returnValue == 0) {
                              returnValue = o1.getVariant().compareTo(o2.getVariant());
                          }
                      }
                      return returnValue;
                  }
              };
              java.util.Arrays.sort(allLocales, comparator);
              for (Locale locale : allLocales) {
                  SimpleDateFormat format = (SimpleDateFormat) DateFormat.getTimeInstance(DateFormat.FULL, locale);
                  String today = format.format(new Date());
                  String pattern = format.toPattern();
                  char okay = pattern.contains("ss") ? ' ' : '*';
                  SimpleDateFormat dateTimeFormat = (SimpleDateFormat) DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.FULL, locale);
                  String dateTimePattern = String.format("[%s]", dateTimeFormat.toPattern());
                  System.out.printf("%c %-32s for %-9s %-38s %-49s -> %-10s %-22s%n", okay, today, locale, pattern,
                          dateTimePattern, locale.getDisplayLanguage(), locale.getDisplayCountry());
              }
          }
      }

      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      It's a lot of work to add the specified fields according to local conventions.

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              naoto Naoto Sato
              webbuggrp Webbug Group
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                Updated:
                Resolved: