code: public int decide(LoggingEvent event) {
      if (this.levelToMatch == null) {
        return Filter.NEUTRAL;
      }
  
      boolean matchOccured = false;
  
      if (this.levelToMatch.equals(event.getLevel())) {
        matchOccured = true;
      }
  
      if (matchOccured) {
        if (this.acceptOnMatch) {
          return Filter.ACCEPT;
        } else {
          return Filter.DENY;
        }
      } else {
        return Filter.NEUTRAL;
      }
    }
docs: Return the decision of this filter.
  
  Returns {@link Filter#NEUTRAL} if the <b>LevelToMatch</b> option
  is not set or if there is not match.  Otherwise, if there is a
  match, then the returned decision is {@link Filter#ACCEPT} if the
  <b>AcceptOnMatch</b> property is set to <code>true</code>. The
  returned decision is {@link Filter#DENY} if the
  <b>AcceptOnMatch</b> property is set to false.