tdcommon/src/main/java/thredds/server/catalog/DataRootPathMatcher.java
public @Nonnull DataRoot convert2DataRoot(DataRootExt dataRootExt) {
    DataRoot dataRoot = dataRootExt.getDataRoot();
    if (dataRoot != null) return dataRoot;

    // otherwise must read the catalog that its in
    dataRoot = readDataRootFromCatalog(dataRootExt);
    dataRootExt.setDataRoot(dataRoot);
    return dataRoot;
  }
public @Nonnull DataRoot convert2DataRoot(DataRootExt dataRootExt) {
    DataRoot dataRoot = dataRootExt.getDataRoot();
    if (dataRoot != null) return dataRoot;

    // otherwise must read the catalog that its in
    dataRoot = readDataRootFromCatalog(dataRootExt);
    dataRootExt.setDataRoot(dataRoot);
    return dataRoot;
  }
convert a dataRootExt to a dataRoot