legacy/src/main/java/ucar/nc2/thredds/ThreddsDataFactory.java
private InvAccess getImageAccess(InvDataset invDataset, ucar.nc2.util.CancelTask task, Result result) {

    List<InvAccess> accessList = new ArrayList<>(invDataset.getAccess()); // a list of all the accesses
    while (accessList.size() > 0) {
      InvAccess access = chooseImageAccess(accessList);
      if (access != null) return access;

// next choice is resolver type.
      access = invDataset.getAccess(ServiceType.RESOLVER);

// no valid access
      if (access == null) {
        result.errLog.format("No access that could be used for Image Type %s %n", invDataset);
        return null;
      }

      // deal with RESOLVER type
      String datasetLocation = access.getStandardUrlName();
      InvDatasetImpl rds = openResolver(datasetLocation, task, result);
      if (rds == null)
        return null;

// use the access list from the resolved dataset
      accessList = new ArrayList<>(invDataset.getAccess());
    } // loop over accesses

    return null;
  }
private InvAccess getImageAccess(InvDataset invDataset, ucar.nc2.util.CancelTask task, Result result) {

    List<InvAccess> accessList = new ArrayList<>(invDataset.getAccess()); // a list of all the accesses
    while (accessList.size() > 0) {
      InvAccess access = chooseImageAccess(accessList);
      if (access != null) return access;

// next choice is resolver type.
      access = invDataset.getAccess(ServiceType.RESOLVER);

// no valid access
      if (access == null) {
        result.errLog.format("No access that could be used for Image Type %s %n", invDataset);
        return null;
      }

      // deal with RESOLVER type
      String datasetLocation = access.getStandardUrlName();
      InvDatasetImpl rds = openResolver(datasetLocation, task, result);
      if (rds == null)
        return null;

// use the access list from the resolved dataset
      accessList = new ArrayList<>(invDataset.getAccess());
    } // loop over accesses

    return null;
  }
look for an access method for an image datatype