[threeten-dev] javax.time.format.DateTimeFormattter#toFormat(Class<?> parseType) API specification

[yoshito_umaoka at us.ibm.com]

Hi all,

I have some comments and questions about public Format 
DateTimeFormatter#toFormat(Class<?> parseType) API specification [
http://threeten.sourceforge.net/apidocs-2012-10-25/javax/time/format/DateTimeFormatter.html#toFormat%28java.lang.Class%29
].

The specification says:

"Returns this formatter as a java.text.Format instance that will parse to 
the specified type."

I think the implementation is likely supporting only some known object 
types and the method would throw IllegalArgumentException or something if 
the given parseType is not supported. I think the spec should clarify what 
kind of argument is likely supported here and type of exception (or 
returning null?) when unsupported type is specified.

Also, it says:

"The format will throw IndexOutOfBoundsException in line with those thrown 
by the print and parse methods."

This description does not sound right. My understanding is "The format" is 
an instance of java.text.Format subclass. Format defines two parse methods 
- 1) Object parseObject(String) and 2) abstract Object parseObject(String, 
ParsePosition) - I do not know what "print" method in the spec actually 
means (Format defines "format" methods, not "print"). In addition to 
these, it's difficult to understand why IndexOutOfBoundsException might be 
thrown by "The format". By the contract of java.textFormat, format method 
should not throw any exception and parseObject should throw 
java.text.ParseException on parse failure. So I have no idea where this 
IndexOutOfBoundsException come from.

Thanks,
Yoshito Umaoka (ICU Project at IBM)