RFR 8080225 FileInput/OutputStream/FileChannel cleanup should be improved

[Peter Levart]

On 12/04/2017 02:25 PM, Peter Levart wrote:
> Hi Rogger,
>
> On 12/04/2017 02:17 PM, Peter Levart wrote:
>> Hi Rogger,
>>
>> Interesting approach. Conditional finalization. You use finalization 
>> to support cases where user overrides finalize() and/or close() and 
>> Cleaner when he doesn't.
>>
>> I wonder if it is the right thing to use AltFinalizer when user 
>> overrides finalize() method. In that case the method is probably not 
>> empty and calls super.finalize() (if it is empty or doesn't call 
>> super, user probably doesn't want the finalization to close the 
>> stream) and so normal finalization applies. If you register 
>> AltFinalizer for such case, close() will be called twice.
>
> Ah, scrap that. I forgot that XXXStream.finalize() is now empty, so 
> user overriding it and calling super does not in fact close the 
> stream. You have to register AltFinalizer in that case. But now I 
> wonder if the logic should still be 3-state and do the following:
>
> - if user overrides finalize() - use AltFinalizer to call both: first 
> finalize() and then close(); else
> - if user overrides close() - use AltFinalizer to call close(); else
> - use Cleaner
>
> What do you think?
>
> Regards, Peter
>

I just realized that in the above case when finalize is overridden, it 
would be called twice. once by finalization and once by AltFinalizer. So 
your logic is as correct as it can be for that case (to just call 
close() with AltFinalizer). The only problem is order which is 
arbitrary, so it may happen that AltFinalizer calls close() 1st and then 
finalization calls overridden finalize() method which might expect the 
stream to still be open until it calls super.finalize().

Regards, Peter