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Date: Thu, 15 Aug 2002 17:12:44 +0200
From: Bjoern Feustel <feustel@espresto.com>
To: lucene-user@jakarta.apache.org
Subject: WildcardQuery (and FuzzyQuery) problems or bugs?
Message-ID: <20020815151244.GC1168@espresto.com>
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Hi,

  i've got problems while using wildcard and fuzzy searches.

While indexing a bunch of documents it could happen that a field of all
documents will be left empty (empty String).

I don't know wether this field will be included into the index at all.

But this leads to a problem while searching. If i create some Queries
(actually this does the QueryParser for me) on that field and run a
search with these queries, i would expect no results.

However, WildcardQuery and FuzziQuery sometimes generate a
NullPointerException in WildcardTermEnum.termCompare(...).

It seems to me that this does not happen if i add an additional unused
field to all documents but it may be that this works for me due to other
reasons. To explain what i mean, i've attached some lines of test code.

btw: I'm using lucene nightly-build 20020814.

Am i missing something or is this a bug?

Another question: An WildcardQuery that is constructed of only
non-wildcards gives me an StringIndexOutOfBoundsException while
searching. Shouldn't this be handled in a smarter way?

Thanks in advance,

  Bjoern


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import org.apache.lucene.search.*;
import org.apache.lucene.index.*;
import org.apache.lucene.store.*;
import org.apache.lucene.analysis.*;
import org.apache.lucene.document.*;
import org.apache.lucene.queryParser.*;

public class Tester {

	public void testMe (boolean additionalField) throws Exception {
		RAMDirectory indexStore = new RAMDirectory();
		IndexWriter writer = new IndexWriter(indexStore, new SimpleAnalyzer(), true);
		Document doc = new Document();
		doc.add(Field.Text("bar0", "foo"));
		doc.add(Field.Text("bar1", ""));

		// magical unused extra field
		if (additionalField)
			doc.add(Field.Text("bar2", "foo"));

		writer.addDocument(doc);
		writer.optimize();
		writer.close();

		IndexSearcher searcher = new IndexSearcher(indexStore);

		Query[] queries = new Query[3];
		queries[0] = new WildcardQuery(new Term("bar0", "f?o"));	// works as expected
		queries[1] = new TermQuery(new Term("bar1", "foo"));		// this one too
		queries[2] = new WildcardQuery(new Term("bar1", "f?o"));	// strange

		Hits result;

		for (int q = 0; q < queries.length; q++) {
			System.out.println ("Query " + q + " (" + queries[q].getClass().getName() + ")");
			System.out.println ("\ttoString (\"bar0\") = " + queries[q].toString ("bar0"));
			System.out.println ("\ttoString (\"bar1\") = " + queries[q].toString ("bar1"));

			result = searcher.search(queries[q]);

			if (result.length() == 0) {
				System.out.println ("\tno results");
			}
			for (int i = 0; i < result.length(); i++) {
				Document d = result.doc(i);
				System.out.println ("\tresult: " + d.get ("bar0") + " - " + d.get ("bar1"));
			}
		}
	}

	public static void main(String[] _argv) {
		Tester t = new Tester();
		try {
			System.out.println ("## With additional unused extra field it works");
			t.testMe(true);
		}
		catch (Throwable th) {
			System.err.println ("OOPS: " + th.getMessage());
			th.printStackTrace();
		}
		try {
			System.out.println ("\n## Without additional unused extra field it won't work");
			t.testMe(false);
		}
		catch (Throwable th) {
			System.err.println ("OOPS: " + th.getMessage());
			th.printStackTrace();
		}
	}
}


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