public class AccessLogger {
    private static ThreadLocal<AdditionalInfo> currentInfo = new ThreadLocal<>();

    public static String getAndRemoveAdditionalInfo() {
        AdditionalInfo additionalInfo = currentInfo.get();
        currentInfo.remove();
        return additionalInfo.getInfo();
    }
    public static void setAdditionalInfo(String info){
        currentInfo.set(new AdditionalInfo(info));
    }
    public static final class AdditionalInfo {
        private String info;
        public AdditionalInfo(String info) {
            super();
            this.info = info;
        }
        public String getInfo() {
            return info;
        }
    }
}

public class AdditionalInfoConverter extends AccessConverter  {
    @Override
    public String convert(IAccessEvent event) {
        String info = AccessLogger.getAndRemoveAdditionalInfo();
        return info!=null ? info : "-";
    }
}

public class AccessLogLayoutWrapper extends PatternLayoutEncoderBase<IAccessEvent> {
    @Override
    public void start() {
        PatternLayout patternLayout = new PatternLayout();
        patternLayout.getDefaultConverterMap().put("X", AdditionalInfoConverter.class.getName());
        patternLayout.setContext(context);
        patternLayout.setPattern(getPattern());
        patternLayout.start();
        this.layout = patternLayout;
        super.start();
    }
}