RollingPolicy rollingPolicy = rollingFileAppender.getRollingPolicy();
if (rollingPolicy == null)
return null;
if (rollingPolicy instanceof RollingPolicyBase) {
RollingPolicyBase policy = (RollingPolicyBase) rollingPolicy;
String fileNamePattern = policy.getFileNamePattern();
Context context = rollingFileAppender.getContext();
File dir = null;
FileNamePattern pattern = new FileNamePattern(fileNamePattern,
context);