/*
* $Header$
* $Revision: 3131 $
* $Date: 2009-10-03 08:09:34 +1000 (Sat, 03 Oct 2009) $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 2003-2009 The JRDF Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* the JRDF Project (http://jrdf.sf.net/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The JRDF Project" and "JRDF" must not be used to endorse
* or promote products derived from this software without prior written
* permission. For written permission, please contact
* newmana@users.sourceforge.net.
*
* 5. Products derived from this software may not be called "JRDF"
* nor may "JRDF" appear in their names without prior written
* permission of the JRDF Project.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the JRDF Project. For more
* information on JRDF, please see <http://jrdf.sourceforge.net/>.
*
*/
package org.jrdf.query.execute;
import org.jrdf.query.expression.BiOperandExpression;
import org.jrdf.query.expression.Expression;
import java.util.Collection;
import static java.util.Collections.sort;
import java.util.LinkedList;
import java.util.List;
/**
* @author Yuan-Fang Li
* @version $Id :$
*/
public class BiOperandExpressionSimplifierImpl implements BiOperandExpressionSimplifier {
private ExpressionComparator<Integer> comparator;
public BiOperandExpressionSimplifierImpl(ExpressionComparator<Integer> newComparator) {
this.comparator = newComparator;
}
public List<Expression> flattenAndSortConjunction(BiOperandExpression conjunction, Class<?> expClass) {
List<Expression> constraintList = new LinkedList<Expression>();
flattenExpression(conjunction, constraintList, expClass);
reorderExpressionList(constraintList);
return constraintList;
}
private void reorderExpressionList(List<Expression> constraintList) {
sort(constraintList, comparator);
}
private void flattenExpression(BiOperandExpression expression, Collection<Expression> set, Class<?> expClass) {
final Expression lhs = expression.getLhs();
final Expression rhs = expression.getRhs();
addExpressionToCollection(lhs, set, expClass);
addExpressionToCollection(rhs, set, expClass);
}
private void addExpressionToCollection(Expression expression, Collection<Expression> set, Class<?> expClass) {
if (expClass.isAssignableFrom(expression.getClass())) {
flattenExpression((BiOperandExpression) expression, set, expClass);
} else {
set.add(expression);
}
}
}