Removing metrics service implementation

[jzonthemtn]

Removing metrics service implementation for #122.

[robfromboulder]

Looks good :-)

[robfromboulder]

The functionality here looks good -- but I think I'm seeing a significant drop in performance with these changes. I ran out of time tonight to gather more details but wanted to give a head's up that this might need more testing before merging.

[jzonthemtn]

Interesting. It's probably the LoggingMetricsService that uses log4j to output those metrics. I will take a look.

[jzonthemtn]

Changed to NoOpMetricsService. The other one will go into Philter. Performance is more important than metrics, by default.

[robfromboulder]

Sounds good!

BTW I think the issue was logFilterTime() was calling LOGGER.debug(...) where the debug string is expensive to calculate. Changing this to if (LOGGER.isDebugEnabled()) LOGGER.debug(...) seemed to resolve the issue.

Agree that NoOpMetricsService is a better default -- but you may wanna add that isDebugEnabled check on the Philter side?

[robfromboulder]

Just tried a few performance tests and it's looking good now, many thanks!