code: public static DataSource create(DataSource ds, Log log) {
          if (ds == null) {
              throw new IllegalArgumentException();
          }
          if (log == null) {
              log = LogFactory.getLog(LoggingDataSource.class);
          }
          if (!log.isDebugEnabled()) {
              return ds;
          }
          return new LoggingDataSource(log, ds);
      }
docs: Wraps the given DataSource which logs to the given log. If debug logging
  is disabled, the original DataSource is returned.