CloseableStream exceptions [was: Re: experience trying out lambda-8-b74]

[Zhong Yu]

I agree %100 with Peter - unchecked wrapper exception here would be
more consistent and more convenient.

On Mon, Feb 4, 2013 at 2:35 PM, Peter Levart <peter.levart at gmail.com> wrote:
>
> On 02/04/2013 08:45 PM, Alan Bateman wrote:
>> On 04/02/2013 19:02, Peter Levart wrote:
>>>
>>> I think that every new API or feature takes some time to get used. When
>>> try-with-resources was introduced, nobody was thinking to use it just
>>> because of java.io methods throwing checked IOException. I aggree that
>>> now many programmers mentally associate IOException with
>>> try-with-resources and you want to piggy-back on that mental perception.
>>> You might get quick response at the beginning, but for the price of
>>> long-term ugliness of exception handling when using the API. I expect
>>> people would be asking for another factory method throwing
>>> UncheckedIOException in JDK9 after the API is going to get used
>>> massively...
>>>
>> All methods to open or access files, directories, etc. in this API
>> throw the checked IOException. It would be inconsistent to introduce a
>> parallel set of methods at this point, particularly because this API
>> also defines also many specific IOExceptions for cases where recovery
>> might be required for specific cases.
>
> Are the specific IOExceptions only relevant when creating the stream or
> also when consuming and/or closing it?
>
>>
>> So I think if CloseableStream is used in a try-with-resources that
>> opens the file or directory then it will probably lead to usages such as:
>>
>> try (...) {
>>      :
>> } catch (UncheckedIOException e) {
>>     throw e.getCause();
>> }
>
> The above example would stay exactly the same if the factory method
> threw UncheckedIOException.
>
>>
>> or
>>
>> try (...) {
>>     :
>> } catch (IOException ioe) {
>>     throw new UncheckedIOException(ioe);
>> }
>>
>
> The catch and manual wrap in UncheckedIOException in above example would
> not be needed if the factory method threw UncheckedIOException already...
>
>> depending on whether you want to propagate a checked or unchecked
>> exception. One of two examples in the javadoc might help.
>>
>> -Alan.
>>
>
> Regards, Peter
>
>