/*
* eXist Open Source Native XML Database
* Copyright (C) 2013 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* $Id$
*/
package org.exist.xquery;
/**
* Base class to be implemented by an index module if it wants to rewrite
* certain query expressions. Subclasses should overwrite the rewriteXXX methods
* they are interested in.
*
* @author Wolfgang Meier
*/
public class QueryRewriter {
private final XQueryContext context;
public QueryRewriter(XQueryContext context) {
this.context = context;
}
/**
* Rewrite the expression to make use of indexes. The method may also return an additional
* pragma to be added to the extension expression which is inserted by the optimizer.
*
* @param locationStep
* @return
* @throws XPathException
*/
public Pragma rewriteLocationStep(LocationStep locationStep) throws XPathException {
return null;
}
protected XQueryContext getContext() {
return context;
}
}