Codereview request for 8006295: Base64.Decoder.wrap(java.io.InputStream) returns InputStream which throws unspecified IOException on attempt to decode invalid Base64 byte stream

[Mark Sheppard]

Hi Alan,

I think it would be useful to convey some additional information 
relating the cause of the problem, even for diagnostic purposes.

So analogous to CharacterEncodingException which exists for Charsets, 
providing a Base64EncodingException
and Baes64DecodingException as derived from IOException, (as alluded to 
previously by Sherman,) could/would be useful.
However, as the underlying encapsulating InputStream/FilterOutputStream 
is no exposed, and hence the overridden
read/write methods publicly defined, how would such exceptions be 
reconciled against the generalized Output/InputStream returned by wrap()?

Alternatively, perhaps throwing an IOException with an embedded 
Base64Encoding/DecodingException could also be used ?

regards
Mark

On 01/02/2013 11:40, Alan Bateman wrote:
> On 01/02/2013 10:14, Patrick Wright wrote:
>> Would it be appropriate to have a "format" exception extending
>> RuntimeException? That could then be documented in the API, but
>> optional to catch explicitly. "Format exceptions", as a name, are
>> already used for converting numbers and dates, for example. It could
>> be "upgraded" to a checked exception in a later release, it people
>> found it useful. A nice thing about a format exception is you could
>> (possibly) include more detail about where the conversion failed, and
>> why, via fields/getters on the exception.
> This is an InputStream and so will be used with libraries and code
> that will rightly expect it to behave as an InputStream. So I think it
> would be better to keep it as an IOException (whether a specialized
> IOException is needed is debatable). That would be consistent with how
> we handle malformed and unmappable input in other areas.
>
> -Alan.
>