Make URI-ref'd remote OMDoc elements accessible transparently

[clange]

Dear Kristina, don't panic. I continued the discussion about loading referenced objects on demand a bit and create this ticket just as a placeholder that we don't forget it.

Ideas:

• have two constructors on every object: one for creating the object with the real data, the other one that takes an URI reference.
• Idea from Normen: JDOM maybe does something like this ("lazy loading", "loading on demand"), try to find an implementation by some guys who already did it.
• The real object should be loaded on demand, as soon as a method is called. This loading on demand should be implemented in a base class, maybe OMDocElement.

Update:

• Every method checks whether the object is already in the memory; if not, calls the download method to populate the fields in the object.
• Later, a method such as update() may be implemented, which writes the modified object back into the database.

[clange]

Hi Dimitar, please allow me to ask how you solved this -- as this was one of the hardest tasks that I assigned to Kristina last year. Where did you implement the solution?

[dmisev]

Ups, not fixed but duplicate, but now I realize it's not duplicate. In any case it should be easy to do once #16 is completed.

Just to be sure, this would be smth like if there's a <ref href="link"/> then the ref object should be able to return the link object?

[dmisev]

Fixed, for most of the elements.