[logback-user] Compiler selecting wrong Logger method

Tony Trinh tony19 at gmail.com
Mon Feb 13 18:17:43 CET 2012

+1 !!

On Mon, Feb 13, 2012 at 11:47 AM, Chris Pratt <thechrispratt at gmail.com>wrote:

> Sure, it uses an extension of the java.text.MessageFormat syntax that
> allows for unlimited formatted varargs, and allows using dot-notation to
> prevent evaluation of the methods until it's been deemed necessary.  With
> the current libraries (all of them really), you have to evaluate all the
> javabeans that hold the data you are looking to log before it's decided
> whether to log the information or not.  In other words:
> log.debug("Loading Student [" + sdnt.getNumber() + "] " + sdnt.getName()
> + " Enrolled: " + new SimpleDateFormat("yyyy-MM-dd").format(sdnt.
> getEnrollmentDate()));
> Means that a lot of work is done and discarded when the debug level on
> this file is set to info or less.  SLF4j is a little better, but not much:
> log.debug("Loading Student [{}] {} Enrolled: {}",new Object[] {sdnt.
> getNumber(),sdnt.getName(),new SimpleDateFormat("yyyy-MM-dd").format(sdnt.
> getEnrollmentDate())});
> Yes, of course you could (and probably should) wrap each and every call to
> the log system in if(log.isDebugEnabled()) {}.  But we all know that is
> ugly and easy for Jr programmers to forget.  My library puts off the
> evaluation until after it's been decided that the information is necessary,
> then efficiently outputs the message, like this:
> log.debug("Loading Student [{0.number}] {0.name} Enrolled:
> {0.enrollmentDate,date,yyyy-MM-dd}",student);
> No muss, no fuss and the TextFormat utility is completely usable
> standalone (as well as the advanced dot-notation utilities).
>    (*Chris*)
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