I'm parsing third party log files containing date/time using Joda. The date/time is in one of two different formats, depending on the age of the log files I'm parsing.
Currently I have code like this:
try {
return DateTimeFormat.forPattern("yyyy/MM/dd HH:mm:ss").parseDateTime(datePart);
} catch (IllegalArgumentException e) {
return DateTimeFormat.forPattern("E, MMM dd, yyyy HH:mm").parseDateTime(datePart);
}
This works but contravenes Joshua Bloch's advice from Effective Java 2nd Edition (Item 57: Use exceptions only for exceptional conditions). It also makes it hard to determine if an IllegalArgumentException occurs due to a screwed up date/time in a log file.
Can you suggest a nicer approach that doesn't misuse exceptions?
You can create multiple parsers and add them to the builder by using DateTimeFormatterBuilder.append method:
DateTimeParser[] parsers = {
DateTimeFormat.forPattern( "yyyy-MM-dd HH" ).getParser(),
DateTimeFormat.forPattern( "yyyy-MM-dd" ).getParser() };
DateTimeFormatter formatter = new DateTimeFormatterBuilder().append( null, parsers ).toFormatter();
DateTime date1 = formatter.parseDateTime( "2010-01-01" );
DateTime date2 = formatter.parseDateTime( "2010-01-01 01" );