[jsword-devel] Loggers

[Chris Burrell]

I guess my more general question is why "We want that when we are handling
errors. Maybe we don't want to do it for all levels of logging. I.e.
configure it."

Doesn't the Java Logger do that? Given we're wrapping around
java.util.loggin.Logger anyway, why not just use those directly. The only
reason I can find is that someone preferred the log4j api to the
java.util.logging api. With Slf4j a developer of a third-party application
can change the way these logs are output anyway, so I can configure a
java.util.logging.Logger via a "log4j.properties" file using the bindings
provided by slf4j.

When I've tried configuring the Loggers occasionally for JSword I have to
say I've found it pretty difficult to work out, for 2 main reasons.
Everything looks like it's using log4j, but the .properties file uses the
java.util.logging.Logger style. My problem was then two-fold: i haven't
used that much, and without digging into the implementation, it's difficult
to know how the log levels match up to the log4j log levels.

Anyhow, just a thought.

Chris



On 6 February 2013 09:37, Chris Burrell <chris at burrell.me.uk> wrote:

> Yeah, i think that will help. I can do the first one. I'm not promising I
> go through the whole code base to do the others.
>
> Chris
>
>
>
> On 5 February 2013 23:38, DM Smith <dmsmith at crosswire.org> wrote:
>
>> Logger.doLogging needs to change to test the level against set level and
>> bail if it is not going to be recorded.
>>
>> There will still be some building of messages outside. We can add a
>> boolean shouldLog(logLevel) to help one determine on whether to construct a
>> log message.
>>
>> Will that help?
>>
>> -- DM
>>
>> On Feb 5, 2013, at 6:22 PM, Chris Burrell <chris at burrell.me.uk> wrote:
>>
>> The 10% logging was debug logging, perhaps that was exacerbated during
>> profiling, but i'd expect it to be exacerbated uniformly-sh.
>>
>> The JSword logger doesn't define a isDebugEnabled as far as I can see.
>> Also, showLocation is true by default, so lots of work happens every time.
>> The logger implementation seems to rely on the underlying functionality as
>> to whether it is logged out to a screen/stream/file/etc. but by then all
>> the work has been done.
>>
>> Due to the missing isDebugEnable type functions, JSword methods across
>> the board presumably do quite a lot of concatenation before even calling
>> the logger, i.e. passing a concatenation of parameters. (not sure whether
>> the profiler would wrap that into the log call, or the caller method,
>> probably the caller)
>>
>> Unfortunately, the third party is not in charge of showLocation. And
>> can't change it as the moment except on a per logger basis. Perhaps it was
>> the particular operation. It's partly because of String concatenations.
>>
>> Cheers
>> Chris
>>
>>
>>
>> On 5 February 2013 23:04, DM Smith <dmsmith at crosswire.org> wrote:
>>
>>>
>>> On Feb 5, 2013, at 3:37 PM, Chris Burrell <chris at burrell.me.uk> wrote:
>>>
>>> > Hi
>>> >
>>> > I was doing a bit of performance tuning for STEP earlier, to see how I
>>> could speed up some of the searches. I found that possibly up to 10% of the
>>> time could be spent logging.
>>>
>>> Seem strange that 10 percent of the time is managing errors. (You need
>>> to look into configuring the logger to only log errors, if you aren't
>>> already). Then the calls to logger are lightweight. Pretty much a no-op.
>>>
>>> There's a bug in changing the LogLevel and in specifying the logger
>>> config. But I don't remember.
>>>
>>> >
>>> > I'm guessing that's because of the bit that tries to throw an
>>> Exception to capture the stack trace.
>>>
>>> We want that when we are handling errors. Maybe we don't want to do it
>>> for all levels of logging. I.e. configure it.
>>>
>>> See the "showLocation" part of the getLogger() call.
>>>
>>> >
>>> > Is there any reason why we're not using the java loggers directly?
>>>
>>> We are using the java loggers. We don't use it directly since we were
>>> using a different logger before the java loggers.
>>>
>>> > Or why we're not using log4j (i see there's a not about keeping it
>>> small)
>>>
>>> That's what we were using.
>>>
>>> The philosophy of JSword architecture is to:
>>> define an abstract interface
>>> create a basic implementation of the abstraction
>>> use a plugin to define which implementation is being used. (Not used wrt
>>> logging)
>>>
>>> By hiding behind the concrete abstraction, we were able to swap out
>>> implementations.
>>>
>>> Hope this helps,
>>>         DM
>>>
>>>
>>>
>>
>>
>
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