/*
* 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.io.IOException;
import java.util.List;
import java.util.ArrayList;
import org.apache.jackrabbit.core.query.lucene.MultiColumnQueryHits;
import org.apache.jackrabbit.core.query.lucene.ScoreNode;
import org.apache.jackrabbit.core.query.lucene.HierarchyResolver;
import org.apache.jackrabbit.spi.commons.query.qom.ChildNodeJoinConditionImpl;
import org.apache.lucene.index.IndexReader;
/**
* <code>ChildNodeJoin</code> implements a child node join condition.
*/
public class ChildNodeJoin extends AbstractCondition {
/**
* A score node map with the score nodes from the inner query hits, indexed
* by the document number of the parent node.
*/
private final ScoreNodeMap parentIndex = new ScoreNodeMap();
/**
* The index reader.
*/
private final IndexReader reader;
/**
* The hierarchy resolver.
*/
private final HierarchyResolver resolver;
/**
* Reusable array of document numbers.
*/
private int[] docNums = new int[1];
/**
* Reusable list of score nodes.
*/
private List<ScoreNode[]> tmpScoreNodes = new ArrayList<ScoreNode[]>();
/**
* Creates a new child node join condition.
*
* @param parent the inner query hits.
* @param reader the index reader.
* @param resolver the hierarchy resolver.
* @param condition the QOM child node join condition.
* @throws IOException if an error occurs while reading from the index.
*/
public ChildNodeJoin(MultiColumnQueryHits parent,
IndexReader reader,
HierarchyResolver resolver,
ChildNodeJoinConditionImpl condition)
throws IOException {
super(parent);
this.reader = reader;
this.resolver = resolver;
int idx = getIndex(parent, condition.getParentSelectorQName());
ScoreNode[] nodes;
while ((nodes = parent.nextScoreNodes()) != null) {
Integer docNum = nodes[idx].getDoc(reader);
parentIndex.addScoreNodes(docNum, nodes);
}
}
/**
* {@inheritDoc}
* <p>
* The outer query hits loop contains the child nodes.
*/
public ScoreNode[][] getMatchingScoreNodes(ScoreNode child) throws IOException {
docNums = resolver.getParents(child.getDoc(reader), docNums);
tmpScoreNodes.clear();
for (int docNum : docNums) {
ScoreNode[][] sn = parentIndex.getScoreNodes(docNum);
if (sn != null) {
for (ScoreNode[] aSn : sn) {
tmpScoreNodes.add(aSn);
}
}
}
if (tmpScoreNodes.isEmpty()) {
return null;
} else {
return tmpScoreNodes.toArray(new ScoreNode[tmpScoreNodes.size()][]);
}
}
}