Andreas,
Doesn’t the class documentation of Number [1] provide sufficient clarity, to
wit:
" The specific semantics of the conversion from the numeric value of a
particular Number implementation to a given primitive type is defined by the
Number implementation in question.”
and
“[…] conversions may lose information about the overall magnitude of a numeric
value, may lose precision, and may even return a result of a different sign
than the input. See the documentation of a given Number implementation for
conversion details.”
That said, it might not however hurt slightly to modify the descriptions of
{float,double,int,long}Value() to read something like, for longValue() for
example:
"Returns the value of the specified number as a {@code long}, which may
involve rounding, truncation, or some other narrowing conversion."
Brian
[1] http://docs.oracle.com/javase/8/docs/api/java/lang/Number.html
On Dec 16, 2014, at 4:55 AM, Andreas Lundblad <[email protected]>
wrote:
> I've noticed that the documentation of Number.longValue says:
>
>> Returns the value of the specified number as a long, which may involve
>> rounding or truncation.
>
> BigInteger and BigDecimal does not seem to honor this contract since they
> implement this method by masking out the lower bits of the number (and I've
> found no definition of "rounding" or "truncation" that encompass this
> behavuor). The documentation of these classes even state that "[...] this
> conversion can lose information about the overall magnitude of the BigInteger
> value as well as return a result with the opposite sign."
>
> I suggest the documentation of Number.byteValue/shortValue/intValue/longValue
> should be updated to give room for this type of implementation.
>
> (I filed an issue on this and got a confirmation email with the following
> link: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7000825 Since then
> this page has gone missing. Where did the bug report go, and why didn't I get
> any notification about the removal?)
