How to use RegexTermEnum

[Raf]

Hi,
I am trying to solve the following problem:
In my index I have a "url" field added as Field.Store.YES,
Field.Index.NOT_ANALYZED and I must use this field as a "key" to identify a
document.

The problem is that sometimes two urls can differ only because they contain
a different session id:
i.e.  I would like to identify that
http://digiland.libero.it/forum/viewtopic.php?p=3432879&sid=70acaeab02505591827a90fe5010f45c#3432879
and
http://digiland.libero.it/forum/viewtopic.php?p=3432879&sid=70acaeab505d98a8229c10fe5010f45c#3432879
are the same document!

So I have tried using a regular expression, to ignore the sid and match both
documents: "http://digiland
\\.libero\\.it/forum/viewtopic\\.php\\?p=3432879\\&.*#3432879".

At this point, I would like to retrieve all terms that satisfy my regex so I
tried to use a RegexTermEnum, but it returns to me only one of the two
documents.
Actually, it seems to me that it does not return the "first" match.
So, if I have only one match in my index, RegexTermEnum returns nothing, if
I have two matches, it returns one doc, and so on.

Here you can find a simple test that shows the problem (both assert fail):

<code>
package it.celi.search;

import static org.junit.Assert.assertEquals;

import java.io.IOException;

import org.apache.lucene.analysis.KeywordAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexWriter.MaxFieldLength;
import org.apache.lucene.search.regex.JakartaRegexpCapabilities;
import org.apache.lucene.search.regex.RegexTermEnum;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class RegexLuceneTest {

    private Directory directory;

    @Before
    public void setUp() throws Exception {

        this.directory = new RAMDirectory();
        this.addDocsToIndex();
    }

    @After
    public void tearDown() throws Exception {
    }

    @Test
    public void test() throws IOException {

        IndexReader reader = IndexReader.open(this.directory);
        System.out.println("Num docs: " + reader.numDocs());

        JakartaRegexpCapabilities regexpCapabilities = new
JakartaRegexpCapabilities();

        String urlToSearch = "http://digiland
\\.libero\\.it/forum/viewtopic\\.php\\?p=3432889\\&.*#3432889";
        RegexTermEnum rte = new RegexTermEnum(reader, new Term("url",
urlToSearch), regexpCapabilities);
        int count = 0;
        while (rte.next()) {
            System.out.println(rte.term() + " " + rte.docFreq());
            count++;
        }
        assertEquals(1, count);

        urlToSearch = "http://digiland
\\.libero\\.it/forum/viewtopic\\.php\\?p=3432879\\&.*#3432879";
        rte = new RegexTermEnum(reader, new Term("url", urlToSearch),
regexpCapabilities);
        count = 0;
        while (rte.next()) {
            System.out.println(rte.term() + " " + rte.docFreq());
            count++;
        }
        assertEquals(2, count);

    }

    private void addDocsToIndex() throws IOException {

        IndexWriter writer = new IndexWriter(directory, new
KeywordAnalyzer(), true, MaxFieldLength.UNLIMITED);

        Document doc = new Document();
        doc.add(new Field("url", "
http://digiland.libero.it/forum/viewtopic.php?p=3432879&sid=70acaeab02505591827a90fe5010f45c#3432879";,
Field.Store.YES, Field.Index.NOT_ANALYZED));
        doc.add(new Field("contents", "contenuto documento 1",
Field.Store.YES, Field.Index.NOT_ANALYZED));
        writer.addDocument(doc);

        doc = new Document();
        doc.add(new Field("url", "
http://digiland.libero.it/forum/viewtopic.php?p=3432889&sid=16c7ea74d98a8229c1ddd4800a2738ec#3432889";,
Field.Store.YES, Field.Index.NOT_ANALYZED));
        doc.add(new Field("contents", "contenuto documento 2",
Field.Store.YES, Field.Index.NOT_ANALYZED));
        writer.addDocument(doc);

        doc = new Document();
        doc.add(new Field("url", "
http://digiland.libero.it/forum/viewtopic.php?p=3432879&sid=70acaeab505d98a8229c10fe5010f45c#3432879";,
Field.Store.YES, Field.Index.NOT_ANALYZED));
        doc.add(new Field("contents", "contenuto documento 3",
Field.Store.YES, Field.Index.NOT_ANALYZED));
        writer.addDocument(doc);

        writer.optimize();
        writer.close();
    }

}
</code>

What am I missing?
Thanks.

Bye,
Raf