NotFoundException

[kurzum]

Hi all,

 try {
                IteratorTripleString it = hdt.search(identifier, property, "");
                while (it.hasNext()) {
                    TripleString ts = it.next();
                    ValAgg.put(identifier, ts.getObject().toString(), lang);
                }
            } catch (NotFoundException nfe) {
                //intentionally left blank.
                //hdt.search returns NF exception instead of null or it.hasNext() == false
            }

this is how my code looks like. I find it weird, that I have to leave the catch block empty. But the code works.

[webdata]

Hi Sebastian,

The exception means that one of the terms in the search does not exist in the dictionary.

org.rdfhdt.hdt.exceptions.NotFoundException: String not found in dictionary

In fact, if all terms exist, the result of the query is empty as you mentioned.

But we can change it to return a null iterator if one of the terms doesn't exist (as in hdt-cpp). Please vote with 👍 if you agree to return a null iterator.

[kurzum]

Ok, I see that HDT is special in this respect compared to a database. However, I am not aware of any data structure that throws an exception if something is not found in the database. I can't judge whether this is valuable information that something that is not in the dictionary is queried. I would expect it to just return an empty iterator, if no result is found.

[webdata]

You are right, and essentially it makes no sense to have two different approaches in C++ and Java.

I have added an empty iterator in d26a0af

Now you have the expected empty iterator if a term is not found.