[thredds] Possible changes to thredds.servlet.Viewer interface

• To: thredds <thredds@xxxxxxxxxxxxxxxx>
• Subject: [thredds] Possible changes to thredds.servlet.Viewer interface
• From: Ethan Davis <edavis@xxxxxxxxxxxxxxxx>
• Date: Thu, 15 Jul 2010 13:59:01 -0600

Hi all,

To anyone who has implemented thredds.servlet.Viewer or uses a Viewer
implementation not distributed with the TDS (check for <viewer> elements
in your threddsConfig.xml file) ...

We are considering changing the thredds.servlet.Viewer interface in
order to handle multiple viewers per implementation. We would like to
know who is adding their own Viewer implementation, and if making this
minor change would be a problem.

Currently the interface is

public interface Viewer {

  /**
   * Is this dataset vieweable by me?
   * @param ds the dataset
   * @return  true if viewable
   */
   public boolean isViewable( InvDatasetImpl ds);

  /**
   * Get an HTML fragment link to the viewer JNLP file, for
   * this dataset.
   * Example: "<a href='idv.jnlp?url="+access.getStandardUrlName()+"'>
                 Integrated Data Viewer (IDV) (webstart)</a>"
   *
   * @param ds the dataset to view
   * @param req the request
   * @return HTML fragment string
   */
   public String getViewerLinkHtml( InvDatasetImpl ds,
                               HttpServletRequest req);
}

we might change to something like

public interface Viewer {
   public boolean isViewable( InvDatasetImpl ds);
   public List<String> getViewerLinkHtml(
                           InvDatasetImpl ds,
                           HttpServletRequest req);
}

For more background, see

http://www.unidata.ucar.edu/projects/THREDDS/tech/tds4.2/reference/Viewers.html

This change would mean current implementations of the Viewer interface
could not be used with versions of TDS that included this change until
the Viewer implementations are updated to the new interface.

Thanks,

The THREDDS team