Enable content switching on type- and formatCode

[hnnesv]

Issue raised by Justin on the wiki:

Would it be beneficial to include the formatCode and/or typeCode in the get/deregister methods? I'm just thinking it might be useful information for determining which handler to call. Many different types of document may have "text/xml" as their mimeType and this might be insufficient for determining the appropriate contenthandler.
See: http://motorcycleguy.blogspot.ca/2013/05/classifying-documents-in-xds.html.

We could alter the signatures as follows:

ContentHandler getContentHandler(String contentType, String typeCode, String formatCode);
void registerContentHandler(String contentType, String typeCode, String formatCode, ContentHandler prototype) ...;

Perhaps we should even take out the use of contentType and just switch on type- and formatCode? It sounds like they are more useful ito SHR usage?

For generic purposes switching on contentType could be useful I suppose, so we could have two matching paths:

ContentHandler getContentHandler(String contentType);
void registerContentHandler(String contentType, ContentHandler prototype) ...;

ContentHandler getContentHandler(String typeCode, String formatCode);
void registerContentHandler(String typeCode, String formatCode, ContentHandler prototype) ...;

allowing for one or the other...

[rcrichton]

Thanks @justin-fyfe @devcritter.

I completely agree, we should use typeCode and formatCode for the switching if content type is not going to be sufficient. Maybe we should just switch on those and if we have a use case for content type as well in the future then we can add it in.

[justin-fyfe]

One question, would it be possible for a content handler to be able to register itself (or subscribe) to multiple formatCodes? I assume that it is possible for a generic CDA handler (that could handle several PCC templates) to call register for each template that can be handled.

[rcrichton]

I'm not sure if this is possible at the moment, maybe @devcritter can comment further. I definitely think that a content handler should be able to do that though.

[hnnesv]

Yup, they can at the moment (well on contentType).