<configuration>

  <appender name="LIST"
             class="ch.qos.logback.core.read.ListAppender">

    <filter class="ch.qos.logback.core.filter.EvaluatorFilter">
      <Name>myFilter</Name>
      <OnMatch>DENY</OnMatch>
      <Evaluator>
        <Name>mdcEvaluator</Name>
        <Expression>"to be ignored".equals(message)</Expression>
      </Evaluator>
    </filter>
  </appender>

  <root level="debug">
    <appender-ref ref="LIST" />
  </root>
</configuration>