UppercaseNameExpander.java

/*
 * Copyright (c) 2009 Andrejs Jermakovics.
 * 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Andrejs Jermakovics - initial implementation
 */
package it.unibz.instasearch.indexing.querying;

import it.unibz.instasearch.indexing.Field;

import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause.Occur;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.WildcardQuery;

/**
 * Converts camel-cased file name patterns to wildcard queries.
 * Eg. converts ABC to A*B*C in order to match AbstractBaseClass
 * also AbsBC will match
 */
public class UppercaseNameExpander extends QueryVisitor {

	@Override
	public Query visit(TermQuery termQuery, Field field) {
		
		if( field != Field.NAME )
			return termQuery;
		
		Term term = termQuery.getTerm();
		String text = term.text();
		
		if( text.matches("[A-Z][a-z0-9_]*[A-Z].*") ) { // if has several uppercase letters
			BooleanQuery bq = new BooleanQuery();
			
			bq.add(termQuery, Occur.SHOULD);
			
			String wcText = text.replaceAll("([A-Z][a-z0-9_]*)", "$1*");
			
			Term wcTerm = Field.NAME.createTerm(wcText);
			WildcardQuery wcQuery = new WildcardQuery(wcTerm);
			wcQuery.setBoost( termQuery.getBoost()/2f );
			bq.add(wcQuery, Occur.SHOULD);
			
			return bq;
		}
		
		return super.visit(termQuery, field);
	}
}