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The source code

package org.apache.lucene.search;

/**
 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.analysis.SimpleAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;

import junit.framework.TestCase;

import java.io.IOException;

/**
 * TestWildcard tests the '*' and '?' wildard characters.
 *
 * @author Otis Gospodnetic
 */
public class TestWildcard
    extends TestCase
{
    /**
     * Creates a new TestWildcard instance.
     *
     * @param name the name of the test
     */
    public TestWildcard(String name)
    {
	super(name);
    }

    /**
     * Tests Wildcard queries with an asterisk.
     *
     */
    public void testAsterisk()
        throws IOException
    {
        RAMDirectory indexStore = getIndexStore("body", new String[]
	    { "metal", "metals" }
						);
	IndexSearcher searcher = new IndexSearcher(indexStore);
	Query query1 = new TermQuery(new Term("body", "metal"));
        Query query2 = new WildcardQuery(new Term("body", "metal*"));
        Query query3 = new WildcardQuery(new Term("body", "m*tal"));
        Query query4 = new WildcardQuery(new Term("body", "m*tal*"));
        Query query5 = new WildcardQuery(new Term("body", "m*tals"));

        BooleanQuery query6 = new BooleanQuery();
        query6.add(query5, false, false);

        BooleanQuery query7 = new BooleanQuery();
        query7.add(query3, false, false);
        query7.add(query5, false, false);

	// Queries do not automatically lower-case search terms:
        Query query8 = new WildcardQuery(new Term("body", "M*tal*"));

	assertMatches(searcher, query1, 1);
	assertMatches(searcher, query2, 2);
	assertMatches(searcher, query3, 1);
	assertMatches(searcher, query4, 2);
	assertMatches(searcher, query5, 1);
	assertMatches(searcher, query6, 1);
	assertMatches(searcher, query7, 2);
	assertMatches(searcher, query8, 0);
    }

    /**
     * Tests Wildcard queries with a question mark.
     *
     * @exception IOException if an error occurs
     */
    public void testQuestionmark()
	throws IOException
    {
        RAMDirectory indexStore = getIndexStore("body", new String[]
	    { "metal", "metals", "mXtals", "mXtXls" }
						);
	IndexSearcher searcher = new IndexSearcher(indexStore);
        Query query1 = new WildcardQuery(new Term("body", "m?tal"));
        Query query2 = new WildcardQuery(new Term("body", "metal?"));
        Query query3 = new WildcardQuery(new Term("body", "metals?"));
        Query query4 = new WildcardQuery(new Term("body", "m?t?ls"));
        Query query5 = new WildcardQuery(new Term("body", "M?t?ls"));

	assertMatches(searcher, query1, 1);
	assertMatches(searcher, query2, 2);
	assertMatches(searcher, query3, 1);
	assertMatches(searcher, query4, 3);
	assertMatches(searcher, query5, 0);
    }

    private RAMDirectory getIndexStore(String field, String[] contents)
	throws IOException
    {
        RAMDirectory indexStore = new RAMDirectory();
        IndexWriter writer = new IndexWriter(indexStore, new SimpleAnalyzer(), true);
	for (int i = 0; i < contents.length; ++i) {
	    Document doc = new Document();
	    doc.add(Field.Text(field, contents[i]));
	    writer.addDocument(doc);
	}
	writer.optimize();
	writer.close();

	return indexStore;
    }

    private void assertMatches(IndexSearcher searcher, Query q, int expectedMatches)
	throws IOException
    {
	Hits result = searcher.search(q);
	assertEquals(expectedMatches, result.length());
    }
}
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