[logback-user] commons-compiler required?

Ceki Gulcu ceki at qos.ch
Tue Jan 11 18:36:17 CET 2011

Hi Eric,

I think commons-compiler is needed for Janino 2.6 and later. Logback was 
tested with Janino 2.4.x and 2.5.x.

If you have a need for java-expressions, try GEventEvaluator even if you 
are not familiar with the Groovy language. Contrary to 
JaninoEventEvaluator which understands simple expressions, 
GEventEvaluator can parse blocks of code. As an example, with using 
Janino you would write:

   ( logger.equals("org.apache.http.wire")  &&
        (mdc != null && mdc.get("entity") != null
        ((String) mdc.get("entity")).contains("someSpecialValue"))

In Groovy, this would become:

      return true;

    if(mdc?.get("entity") == null)
      return false;

    String payee = (String) mdc.get("entity");

    if(logger.equals("org.apache.http.wire") &&
      payee.contains("someSpecialValue") &&
      !message.contains("someSecret")) {
      return true;

    return false;

Note the Groovy expression is almost valid Java. My point is that for 
most non-trivial expressions the Groovy version will be easier to write 
and to read.

Note that while Groovy has advantages over Java as language, the biggest 
difference between JaninoEventEvaluator and GEventEvaluator is due to 
the former's limitation to boolean expressions. This limitations is 
likely to be removed in a future version of logback.


On 11.01.2011 17:12, Eric Hough wrote:
> Hi,
> I'm using Janino with logback to utilize evaluators after installing
> Janino as described at http://logback.qos.ch/setup.html. It's working
> great.
> However I noticed that over on Janino's site
> (http://docs.codehaus.org/display/JANINO/Download#Download-installation)
> they require commons-compiler.jar. My question is, does Logback also
> require commons-compiler.jar? I just want to make sure I don't run
> into a ClassNotFoundException down the road.
> Thanks!

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