public RackLogger getLogger() {
if (logger == null) {
String loggerClass = getLoggerClassName();
if ( "stdout".equalsIgnoreCase(loggerClass) ) {
logger = new OutputStreamLogger(getOut());
}
else if ( "stderr".equalsIgnoreCase(loggerClass) ) {
logger = new OutputStreamLogger(getErr());
}
else {
final Map<String, String> loggerTypes = getLoggerTypes();
final String loggerKey = loggerClass.toLowerCase();
if (loggerTypes.containsKey(loggerKey)) {