Joda Time bug or my mistake? (Java Joda Time dates as strings parsing)

Question

so I was having a problem parsing a date, using the JodaTime chronology `IslamicChronology` so wrote a small example to demonstrate my problem. Here's the code: ``` import org.joda.time.Chronology; import org.joda.time.format.DateTimeFormatter; import org.joda.time.format.DateTimeFormat; import org.joda.time.chrono.IslamicChronology; import java.util.Date; /** * Test */ public class Test { public static void main(String[] args) { Date now = new Date(); String format = "dd MMM yyyy"; Chronology calendarSystem = IslamicChronology.getInstance(); DateTimeFormatter formatter = DateTimeFormat.forPattern(format).withChronology(calendarSystem); String nowAsString = formatter.print(now.getTime()); System.out.println("nowAsString = " + nowAsString); long parsedNowTs = formatter.parseMillis(nowAsString); String parsedNowTsAsString = formatter.print(parsedNowTs); } } ``` And the output: ``` nowAsString = 16 10 1430 Exception in thread "main" java.lang.IllegalArgumentException: Invalid format: "16…

Accepted Answer

If anyone's interested...I've found a work around:

- Create a new class e.g. `IslamicChronologyWithNames` which delegates to an instance of `IslamicChronology` in package org.joda.time.DateTimeZone

- Modify the one method; `assemble(Fields fields)`: call the delegate's method and then set fields.monthOfYear (and possibly dayOfWeek) to you own subclass of `BasicMonthOfYearDateTimeField`

- The subclass of `BasicMonthOfYearDateTimeField` can then lookup in property files names for the month's (or day's if DayOfWeek...) name. Subclass needs to be in package org.joda.time.chrono to be able to extend `BasicMonthOfYearDateTimeField`.

There is still an issue that Joda time seems to validate the date you are parsing before calling methods of subclass like `getAsText(int fieldValue, Locale locale)` and because it has no knowledge of the month names that your class returns, fails validation and so never calls the methods. My work-around was to have a static method in this class which converts a date as a string with islamic month names into a date as a string with gregorian english month names. So before calling `parseDateTime()`, call the static method and then the date string passes validation. Then, instead of processing Islamic month names in the `convertText()` method, use the default gregorian implementation inside your subclass:

```
protected int convertText(String text, Locale locale)
{
    return GJLocaleSymbols.forLocale(locale).monthOfYearTextToValue(text);
}
```

That should work! Hope it makes sense for anyone who has the same problem.

Joda Time bug or my mistake? (Java Joda Time dates as strings parsing)

Solution

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