erickerickson at gmail
Sep 22, 2008, 8:42 AM
Post #4 of 5
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Re: How specify the analyzer when created query with api?
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Right, you can't do that. TermQuerys are low-level, they don't
go through analyzers, you have to do the tokenizing yourself.
StandardAnalyzer, among other things, lowercases the tokens.
If you haven't already got a copy of Luke, please do so as it's
a wonderful tool for seeing what different analyzers do. Not to
mention examining your index. Not to mention....
You could do something like
BooleanQuery bq = new BooleanQuery()
Query q = queryParser.parse("Lucene")
bq.add(q, BooleanClause.Occur.MUST)
Hits result = luceneContext.search(bq);
but I don't know whether this suits your needs.
You're still testing the query parser rather than
testing building BooleanQuerys.
(note, I haven't compiled this....).
BTW, the reason your test is failing is because
of the case issue, I believe. You'd get the
results you expect if you did something like:
luceneContext.search(new TermQuery(new
Term(LuceneContext.TITLE, "lucene")));
(not lower-case "lucene").
You could also do something like getting the
tokenStream from StandardAnalyzer call
next(), adding each returned token as a new
Term to your BooleanQuery.
But TermQuery etc. are different beasts than the
a parsed query.
But isn't this the wonderful thing about tests? They
make your assumptions explicit, and when your
assumptions are incorrect, you find it with much less
pain than in a working program where you say "the most
recent change I made couldn't possibly have broken
anything" <G>.
Best
Erick
On Mon, Sep 22, 2008 at 10:01 AM, Giannandrea Castaldi <g.castaldi[at]gmail.com
> wrote:
> On Mon, Sep 22, 2008 at 2:49 PM, Erick Erickson <erickerickson[at]gmail.com>
> wrote:
> > What do you mean when you say "trying to use the lucene api to build
> > queries"?
> > Are you trying to use BooleanQuery? If so, you either construct specific
> > clauses yourself (presumably by, say, tokenizing things yourself and
> > creating TermQuerys, PhraseQuerys, etc.) which *don't* need an
> > analyzer, or add Querys that you get from running stuff through
> > QueryParser that has a constructor that takes an Analyzer.
> >
> > Code snippets or more specific questions would be a great help <G>...
> > Imagine yourself trying to respond to an e-mail like you sent. There
> > isn't enough information there to really understand the problem you're
> > trying to solve, so I have to guess.
>
> Sorry, my question was indeed too generic.
> I've written several tests to take confidence with behavior of Lucene,
> all using the StandardAnalyzer and the QueryParser. All the tests
> pass.
> Now I'm trying to write the same tests using
> Term/TermQuery/BooleanQuery but they don't works. Now I've found out
> that the problem is that using directly Term/TermQuery/BooleanQuery
> I'm not specifying the analyzer and then the query is not correct.
> Here one test with the use of the QueryParser, that works, and the
> current vesion with Term that doesn't work:
>
> @Test
> public void testSimpleSearch() throws Exception
> {
> LuceneContext luceneContext = new LuceneContext();
> Document luceneInAction = luceneContext.createDocument("Lucene
> in action", 193, "9.90");
> Document luceneForDummies =
> luceneContext.createDocument("Lucene for dummies", 245, "11.50");
> Document tomcatInAction = luceneContext.createDocument("Tomcat
> in action", 728, "110.30");
> luceneContext.addDocument(luceneInAction);
> luceneContext.addDocument(luceneForDummies);
> luceneContext.addDocument(tomcatInAction);
> luceneContext.closeIndex();
> QueryParser queryParser = new QueryParser(LuceneContext.TITLE,
> new StandardAnalyzer());
> Hits result = luceneContext.search(queryParser.parse("Lucene"));
> assertEquals(result, Arrays.asList(luceneInAction,
> luceneForDummies));
> }
>
> @Test
> public void testSimpleSearch() throws Exception
> {
> LuceneContext luceneContext = new LuceneContext();
> Document luceneInAction = luceneContext.createDocument("Lucene
> in action", 193, "9.90");
> Document luceneForDummies =
> luceneContext.createDocument("Lucene for dummies", 245, "11.50");
> Document tomcatInAction = luceneContext.createDocument("Tomcat
> in action", 728, "110.30");
> luceneContext.addDocument(luceneInAction);
> luceneContext.addDocument(luceneForDummies);
> luceneContext.addDocument(tomcatInAction);
> luceneContext.closeIndex();
> Hits result = luceneContext.search(new TermQuery(new
> Term(LuceneContext.TITLE, "Lucene")));
> assertEquals(result, Arrays.asList(luceneInAction,
> luceneForDummies));
> }
>
> Now, in our webapp, to execute query on the index we compose a query
> as string passed to QueryParser. We've read on the lucene
> documentation that from code is better compose a BooleanQuery using
> Term/TermQuery/... and then I'm evaluting how do it.
> Thanks.
> jean71
>
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