cdm/src/main/java/ucar/nc2/dataset/NetcdfDataset.java
public static NetcdfFile openFile(DatasetUrl location, int buffer_size, ucar.nc2.util.CancelTask cancelTask, Object spiObject) throws IOException {
    return openOrAcquireFile(null, null, null, location, buffer_size, cancelTask, spiObject);
  }
public static NetcdfFile openFile(DatasetUrl location, int buffer_size, ucar.nc2.util.CancelTask cancelTask, Object spiObject) throws IOException {
    return openOrAcquireFile(null, null, null, location, buffer_size, cancelTask, spiObject);
  }
Factory method for opening a NetcdfFile through the netCDF API. May be any kind of file that
can be read through the netCDF API, including OpenDAP and NcML.
<p>
<p> This does not necessarily return a NetcdfDataset, or enhance the dataset; use NetcdfDataset.openDataset() method for that.

@param location    location of dataset. This may be a
<ol>
<li>local filename (with a file: prefix or no prefix) for netCDF (version 3), hdf5 files, or any file type
registered with NetcdfFile.registerIOProvider().
<li>OpenDAP dataset URL (with a dods:, dap4:, or http: prefix).
<li>NcML file or URL if the location ends with ".xml" or ".ncml"
<li>NetCDF file through an HTTP server (http: prefix)
<li>thredds dataset (thredds: prefix), see DataFactory.openDataset(String location, ...));
</ol>
@param buffer_size RandomAccessFile buffer size, if <= 0, use default size
@param cancelTask  allow task to be cancelled; may be null.
@param spiObject   sent to iosp.setSpecial() if not null
@return NetcdfFile object
@throws java.io.IOException on read error