PrefixQuery and special characters

Datum: Wed, 14 Apr 2010 08:24:38 -0400
Von: Steven A Rowe <[email protected]>
An: "java-[email protected]" <[email protected]>
Betreff: RE: PrefixQuery and special characters
Hi Franz,

The likely problem is that you're using an index-time analyzer that strips
out the parentheses. StandardAnalyzer, for example, does this;
WhitespaceAnalyzer does not.

Remember that hits are the result of matches between index-analyzed terms
and query-analyzed terms. Except in the case of synonyms, most people will
want their index and query analyzers to be the same.

Steve

________________________________________
From: Franz Roth [[email protected]]
Sent: Wednesday, April 14, 2010 7:42 AM
To: [email protected]
Subject: PrefixQuery and special characters

Hi all,

say I have an Index with one field named "category". There are two
documents one with value "(testvalue)" and one with value "test value".
Now somone search with "test". My Searchenine uses the
org.apache.lucene.search.PrefixQuery and finds 2 documents. Maybe he estimated only one hit;
owever: if he searches for "(test" and the Searchengine uses the
QueryParser.escape to clean the request and takes that PrefixQuery to search nothing
results.

How can I search for the document "(testvalue)" and only this one?

Thx!





package foo.bar;

import java.io.IOException;

import junit.framework.TestCase;

import org.apache.log4j.Logger;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.PrefixQuery;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.store.LockObtainFailedException;
import org.apache.lucene.store.RAMDirectory;



public class TestPrefixQuery extends TestCase {
public void testEscapeAndPrefix() throws CorruptIndexException,
LockObtainFailedException, IOException {

RAMDirectory directory = new RAMDirectory();
IndexWriter writer = new IndexWriter(directory, new
StandardAnalyzer(),
true, IndexWriter.MaxFieldLength.LIMITED);
Document doc = new Document();
doc.add(new Field("category", "(testvalue)", Field.Store.YES,
Field.Index.ANALYZED));
writer.addDocument(doc);
doc = new Document();
doc.add(new Field("category", "test value", Field.Store.YES,
Field.Index.ANALYZED));
writer.addDocument(doc);
writer.close();

String value= "test";
PrefixQuery query = new PrefixQuery(new Term("category",
value));
//log.debug(query.toString());
IndexSearcher searcher = new IndexSearcher(directory);
ScoreDoc[] hits = searcher.search(query, null,
1000).scoreDocs;
assertEquals("One for " + value , 2, hits.length); //I want
one for this?!

value= "(test";
String escaped = QueryParser.escape(value);
query = new PrefixQuery(new Term("category", escaped));
//log.debug(query.toString());
hits = searcher.search(query, null, 1000).scoreDocs;
assertEquals("One for " + value + "/" + escaped, 1,
hits.length); //FAILS!
}
}

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