/*
* 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.join;
import java.util.Collection;
import java.util.Comparator;
import javax.jcr.RepositoryException;
import javax.jcr.query.Row;
/**
* Comparator for {@link Row} instances that looks only at the node paths.
*/
public class RowPathComparator implements Comparator<Row> {
private boolean isNullEqual = true;
/**
* a superset of selectors, in cases where there are joins and such, the
* possibility that a selector node does not exist in a row can happen
*/
private Collection<String> selectors = null;
public RowPathComparator(Collection<String> selectors) {
this.selectors = selectors;
}
public RowPathComparator() {
this(null);
}
/**
* Compares two rows.
*/
public int compare(Row a, Row b) {
if (selectors != null) {
// will look at equality for each path in the row
for (String selector : selectors) {
String pA = null;
boolean aExists = true;
String pB = null;
boolean bExists = true;
try {
pA = a.getPath(selector);
} catch (RepositoryException e) {
// non existing A selector
aExists = false;
}
try {
pB = b.getPath(selector);
} catch (RepositoryException e) {
// non existing B selector
bExists = false;
}
// in the case that there is a missing selector node that exists
// on the other row, they are definitely not equal
if ((!aExists && bExists) || (aExists && !bExists)) {
return aExists ? -1 : 1;
}
if (pA == null || pB == null) {
if (!isNullEqual) {
return -1;
}
} else {
int local = pA.compareTo(pB);
if (local != 0) {
return local;
}
}
}
return 0;
}
try {
return a.getPath().compareTo(b.getPath());
} catch (RepositoryException e) {
throw new RuntimeException("Unable to compare rows " + a + " and "
+ b, e);
}
}
}