Re: Lucene cas consumer

Hi all,

I'm using both Lucene and UIMA in one project.

Lucene is primarily an information retrieval API. It provides a
framework and default implementations for analyzing several languages.
Analyzing means tokenization, stop words, etc. Furthermore, it brings
the key functionality to build an inverted index and to search it.

Lucene can be extended easily. E.g. one can implement an analyzer that
does lemmatization or that looks up synonyms in Wordnet  and adds them
to the index.

What Lucene cannot do - or at least not without a lot of hacking - is
aggregating analyses as UIMA can using the CAS. Usually your knowledge
grows during an UIMA-based NLP-pipeline: you add the a token annotation,
a lemma annotation, a POS-annotation and so on...  In Lucene, you have
the classical pipeline: the output replaces the input. (Yes, by
subclassing Lucene's "Token" class, one can fiddle around the issue, but
it is not elegant at all.)

What makes Lucene + UIMA interesting for me is a simple fact: I can do
all the NLP I want and be as flexible as I need in UIMA. Then I can feed
the outcome (or rather: a small part of it) into a Lucene index.

In my special case, I'm not using a CAS Consumer, but I can imagine
other people would appreciate it in their application scenarios.

To conclude: Lucene and UIMA aren't competitors, but in some cases 
having one feeding the other is what you want.