Update filter method for adding isTraceEnabled condition to reduce calls to nanoTime method

Comment From: pivotal-cla

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Comment From: mhalbritter

What's the problem with System.nanoTime?

Comment From: Java4ye

No,I mean the 'startTime' variable takes effect only when 'logger.isTraceEnabled()' , So I add this conditon to it long startTime = 0; if (logger.isTraceEnabled()) { startTime = System.nanoTime(); } And I marked the key points from the image below. @mhalbritter SpringBoot Update filter method

Comment From: mhalbritter

I get that this variable is only used when logging on trace, but have you observed a performance problem with calling System.nanoTime()?

Comment From: Java4ye

@mhalbritter I didn't do that, but I found it in the for loop.

Comment From: wilkinsona

Until something shows up as a performance bottleneck, I think we should leaves things as they are. It may even be that the isTraceEnabled() check is slower than the call to System.nanoTime(). Thanks anyway for the proposal.