Threadsafe Date Formatting

ThreadsafeDF.m

+ (NSDateFormatter *)dateReader
{
  NSMutableDictionary *dictionary = [[NSThread currentThread] threadDictionary];
  NSDateFormatter *dateReader = [dictionary objectForKey:@"SCDateReader"];
  if (!dateReader)
  {
    dateReader = [[[NSDateFormatter alloc] init] autorelease];
    dateReader.locale = [[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"] autorelease];
    dateReader.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
    dateReader.dateFormat = @"EEE, dd MMM yyyy HH:mm:ss Z";
    [dictionary setObject:dateReader forKey:@"SCDateReader"];
  }
  return dateReader;
}

+ (NSDateFormatter *)dateWriter
{
  NSMutableDictionary *dictionary = [[NSThread currentThread] threadDictionary];
  NSDateFormatter *dateWriter = [dictionary objectForKey:@"SCDateWriter"];
  if (!dateWriter)
  {
    dateWriter = [[[NSDateFormatter alloc] init] autorelease];
    dateWriter.locale = [NSLocale currentLocale];
    dateWriter.timeZone = [NSTimeZone defaultTimeZone];
    dateWriter.dateStyle = NSDateFormatterMediumStyle;
    [dictionary setObject:dateWriter forKey:@"SCDateWriter"];
  }
  return dateWriter;
}