How lucene and nucth work together?

Nutch already uses Lucene, in fact it wouldn't be able to do without it.
Nutch creates so called "segments" (meaning is different from Lucene
segments), which can be indexed to produce Lucene indexes, which are
then used for searching.

I suggest to use Luke (http://www.getopt.org/luke) to investigate such
index first, before using it in a separate application. Nutch uses
non-standard analyzer, so that the terms in the index are sometimes
different (e.g. some words are combined into bi-grams).

Andrzej, tanks for the reply.
I'm sorry but i've another (similar) question...
Lucene and nutch use the same parser and analyzer? I seems to understand that the segments created from the nutch are different from those creating from lucene.
I've installed nutch and I've created folders db and segments. Then, as explained in the tutorial, i've created a new database, injected urls into it, generated a fetchlist from the database and indexed the segment with the command
bin/nutch index ..
May I use as lucene's "indexLocation" the index folder created in this way?
If I may not, how can I make a valid index for lucene?

Thanks in advance.

Giovanni
Atitlan Engineering, Pisa

They are not simply different - they represent completely different data
structures, only accidentally named the same...
In Lucene API there is no such thing as "indexLocation". You probably
refer to the search demo application, included in Lucene distribution.
If that's the case, then the answer is no - it won't work with indexes
created by Nutch. However, if you use Lucene API, you can work with them
just fine - they are normal Lucene indexes, just the field names, and
analyzers used are different.

I suggest you to look inside the demo app., and see how Lucene's API is
used.

Andrzej,
I'm so sorry about still disturbing you!

I followed your suggest and i have found this code:

try {
searcher = new IndexSearcher(
IndexReader.open(indexName) //create an indexSearcher for our page
);
} catch (Exception e) {

IndexSearcher is a class of Lucene API, isn't this?

I have used as "indexName" the index created by nutch. When I access the lucene web page of my application, the system not produce any exception, but the result list is always empty (for any search keyword used).

What's wrong?


Thanks in advance.

Giovanni
Atitlan Engineering, Pisa

Lucene doesn't have any "web page" - Lucene is a library. This means
that you are using some kind of web application based on Lucene. The
exact details of how a query is run with the index (e.g. the default
field, analyzer, etc) depend on the application. You cannot just blindly
use a specific application (which assumes specific things about the
index) with any random index, and hope that it works...

Well, perhaps the only exception to that rule would be Luke
(http://www.getopt.org/luke), which you should try anyway to get a
better understanding of what's in the index.
What is the query? What is the analyzer?