SPARQL ElementPathBlock

Question

In am trying to retrieve the triples of a SPARQL expression involved in the OPTIONAL and NON OPTIONAL part of the query, separately.

I used the API ARQ Jena visitor but neither ElementPathBlock nor ElementGroup nor ElementOptional are enough. ElementPathBlock retrieves all the triples, and ElementGroup retrieves the groups of triples (enclosed by {}), and ElementOptional the optional Elements.

Could you help me please?

Answer 1

Thanks for your answer. I found the solution. I was using the ElementWalker as you suggested. However, ElementWalker is not useful (or I could not find the good way) for the traversal of a SPARQL query as usual, I means left-to-right and top-down traversal. I had to write my own method for the traversal of a SPARQL using instanceof, and each type of SPARQL expression: ElementPathBlock, ElementOptional, etc, and recursion. In this way, I was able to extract the optional part (and mandatory part) of the query, as well as union and minus, etc.