legacy/src/main/java/ucar/nc2/thredds/ThreddsDataFactory.java
public NetcdfDataset openDataset(InvDataset invDataset, boolean acquire, ucar.nc2.util.CancelTask task, Formatter log) throws IOException {
    Result result = new Result();
    NetcdfDataset ncd = openDataset(invDataset, acquire, task, result);
    if (log != null) log.format("%s", result.errLog);
    return (result.fatalError) ? null : ncd;
  }
public NetcdfDataset openDataset(InvDataset invDataset, boolean acquire, ucar.nc2.util.CancelTask task, Formatter log) throws IOException {
    Result result = new Result();
    NetcdfDataset ncd = openDataset(invDataset, acquire, task, result);
    if (log != null) log.format("%s", result.errLog);
    return (result.fatalError) ? null : ncd;
  }
Try to open as a NetcdfDataset.

@param invDataset open this
@param acquire    if true, aquire the dataset, else open it
@param task       may be null
@param log        error message, may be null
@return NetcdfDataset or null if failure
@throws IOException on read error