During the KNIME Opensource Days 2011 we(*) agreed on the following: - We need to have uniform URL representation in KNIME in form of a DataCell (part of KNIME table) and a PortObject (custom port type) - Both the cell and port object must represent the same content, they both use a delegate "URLContent" (possibly subclassed). Dedicated nodes allow the conversion between cells (or tables) and port objects. - Nodes that need a URL input should use the dedicated port, not a table (though tables are needed, e.g. in loops etc). - A DataCell represent a single URL, multiple URLs are represented by a table. - A PortObject represents multiple URLs. - A URL may have a MIMEType (really an extension only) associated. It's represented by a MIMEURLContent. - In order to allow access to the MIME type during node configuration, the MIME type is also represented in a MIMEURLPortObject[Spec], which extends the URLPortObject[Spec]. All URLs represented by such an MIMEURLPortObject need to have the same MIME type.

*we = Michael Berthold, Oliver Kohlbacher, Marc R�ttig, Bernd Wiswedel