title: Log4j filter in Grails Log4j DSL configuration
body: <p>Is there a way to specify a log4j filter in <a href="http://grails.org/doc/1.3.7/guide/3.%20Configuration.html#3.1.2%20Logging" rel="nofollow">Grails log4j DSL</a> configuration? I need to define something like this in my Grails log4j config:</p>
  
  <pre><code>&lt;filter class="org.apache.log4j.filter.ExpressionFilter"&gt;
      &lt;param name="expression" value="EXCEPTION ~= com.company.BackendNotAvailableException" /&gt;
      &lt;param name="acceptOnMatch" value="false"/&gt;
  &lt;/filter&gt;
  </code></pre>
  
  <p>I use Grails 1.3.7.</p>