code: @Test public void testSimpleEvaluator() throws NullPointerException, EvaluationException, JoranException {
    JoranConfigurator jc=new JoranConfigurator();
    LoggerContext loggerContext=new LoggerContext();
    jc.setContext(loggerContext);
    jc.doConfigure(ClassicTestConstants.JORAN_INPUT_PREFIX + "simpleEvaluator.xml");
    Map evalMap=(Map)loggerContext.getObject(CoreConstants.EVALUATOR_MAP);
    assertNotNull(evalMap);
    JaninoEventEvaluator evaluator=(JaninoEventEvaluator)evalMap.get("msgEval");
    assertNotNull(evaluator);
    Logger logger=loggerContext.getLogger("xx");
    ILoggingEvent event0=new LoggingEvent("foo",logger,Level.DEBUG,"Hello world",null,null);
    assertTrue(evaluator.evaluate(event0));
    ILoggingEvent event1=new LoggingEvent("foo",logger,Level.DEBUG,"random blurb",null,null);
    assertFalse(evaluator.evaluate(event1));
  }
  