[jsword-devel] NPE in RawFileBackend#getCardinality

[Chris Burrell]

I agree with not coding against dodgy developers (although to be fair I'm
not entirely sure how the conf files have been left over).

But, I'd like to suggest we add a line in the reading of the conf file to
validate that the module data directory actually exists and is non-empty.
If the directory is empty/doesn't exist, we remove the book from the
returned set of installed()

Chris



On 11 February 2013 23:23, DM Smith <dmsmith at crosswire.org> wrote:

> Ah. I see. The JSword code (IIRC) deletes the conf first and then the
> files. I downloaded the module just fine and deleted it from w/in the app
> as well. I think we should not go out of our way for a developer that wacks
> parts of modules. :)
>
> That said, your question regarding the error is still worthy of solving.
> There are many reasons that a backend might fail and it would make sense to
> have robust code to handle such failures.
>
> In Him,
> DM
>
>
>
> On Feb 11, 2013, at 5:59 PM, Chris Burrell <chris at burrell.me.uk> wrote:
>
> Dm
>
> The problem is that I must likely deleted the files. But not the Conf
> file.
> Just wanted to highlight npe as we probably want to avoid having one at
> that stage
> Chris
> On 11 Feb 2013 22:54, "DM Smith" <dmsmith at crosswire.org> wrote:
>
>>
>> On Feb 11, 2013, at 5:27 PM, Chris Burrell <chris at burrell.me.uk> wrote:
>>
>> > Hi
>> >
>> > On line 124, we have a potential NPE:
>> >
>> > state.getIdxRaf() can return a null value if for some reason we are
>> attempting to read the cardinality of a module, but the idx file for the
>> module is not present.
>> >
>> > In this case, I'm looking at the 2babdict module, for which I have a
>> conf file but no module files under modules/lexdict/rawld
>> >
>> > Obviously, this is an issue, but I wonder if the reading of the .conf
>> file should identify the absence of modules and therefore
>> > a- report early to the user that something is wrong
>> > b- not show-up in the list of installed() modules
>>
>> The code regarding backends is in process of change, maybe done.
>>
>> The way the code used to work:
>> For the list of installed books (i.e. for each conf) build an appropriate
>> backend, which would log an error and throw an exception if the files for
>> the module were not present and mark the module as unsupported.
>>
>> The problem with that model is that it is expensive on startup when lots
>> of modules are installed. There is a Jira issue regarding improving this
>> performance.
>>
>> The other problem is that it has no memory of the error and on next
>> startup, it does the work again.
>>
>> It seems to me that when the module is installed, that'd be a great time
>> to validate it fully and mark it as validated.
>>
>> In JSword we have ReporterUtil to let the user know of events like this.
>> It might not work in STEP as it is tied to a listener mechanism.
>>
>> It'd be good to iterate on this to get a good solution.
>>
>> I'm looking at 2babdict to see if I can identify the problem.
>>
>> In Him,
>>         DM
>>
>>
>
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