/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package org.apache.jackrabbit.core.query.lucene.sort;
import static javax.jcr.query.qom.QueryObjectModelConstants.JCR_ORDER_DESCENDING;
import java.util.Comparator;
import javax.jcr.RepositoryException;
import javax.jcr.Value;
import javax.jcr.query.Row;
import javax.jcr.query.qom.Operand;
import javax.jcr.query.qom.Ordering;
import org.apache.jackrabbit.commons.query.qom.OperandEvaluator;
import org.apache.jackrabbit.core.query.lucene.join.ValueComparator;
/**
* Row comparator.
*/
public class RowComparator implements Comparator<Row> {
private static final ValueComparator comparator = new ValueComparator();
private final Ordering[] orderings;
private final OperandEvaluator evaluator;
public RowComparator(Ordering[] orderings, OperandEvaluator evaluator) {
this.orderings = orderings;
this.evaluator = evaluator;
}
public int compare(Row a, Row b) {
try {
for (Ordering ordering : orderings) {
Operand operand = ordering.getOperand();
Value[] va = evaluator.getValues(operand, a);
Value[] vb = evaluator.getValues(operand, b);
int d = comparator.compare(va, vb);
if (d != 0) {
if (JCR_ORDER_DESCENDING.equals(ordering.getOrder())) {
return -d;
} else {
return d;
}
}
}
return 0;
} catch (RepositoryException e) {
throw new RuntimeException("Unable to compare rows " + a + " and "
+ b, e);
}
}
}