1   package ch.qos.logback.core.pattern;
2   
3   import ch.qos.logback.core.pattern.DynamicConverter;
4   
5   public class ExceptionalConverter extends DynamicConverter {
6     
7     public String convert(Object event) {
8       if(!isStarted()) {
9         throw new IllegalStateException("this converter must be started before use");
10      }
11      return "";
12    }
13  
14  }