/*
* 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;
import org.apache.jackrabbit.core.query.lucene.hits.AbstractHitCollector;
import org.apache.jackrabbit.core.query.lucene.hits.Hits;
import org.apache.jackrabbit.core.query.lucene.hits.ScorerHits;
import org.apache.jackrabbit.spi.Name;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.search.Similarity;
import org.apache.lucene.search.Weight;
import java.io.IOException;
import java.util.BitSet;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
/**
* <code>ParentAxisQuery</code> selects the parent nodes of a context query.
*/
@SuppressWarnings("serial")
class ParentAxisQuery extends Query {
/**
* The context query
*/
private final Query contextQuery;
/**
* The nameTest to apply on the parent axis, or <code>null</code> if any
* parent node should be selected.
*/
private final Name nameTest;
/**
* The index format version.
*/
private final IndexFormatVersion version;
/**
* The internal namespace mappings.
*/
private final NamespaceMappings nsMappings;
/**
* The scorer of the context query
*/
private Scorer contextScorer;
/**
* Creates a new <code>ParentAxisQuery</code> based on a
* <code>context</code> query.
*
* @param context the context for this query.
* @param nameTest a name test or <code>null</code> if any parent node is
* selected.
* @param version the index format version.
* @param nsMappings the internal namespace mappings.
*/
ParentAxisQuery(Query context, Name nameTest,
IndexFormatVersion version, NamespaceMappings nsMappings) {
this.contextQuery = context;
this.nameTest = nameTest;
this.version = version;
this.nsMappings = nsMappings;
}
/**
* Creates a <code>Weight</code> instance for this query.
*
* @param searcher the <code>Searcher</code> instance to use.
* @return a <code>ParentAxisWeight</code>.
*/
public Weight createWeight(Searcher searcher) {
return new ParentAxisWeight(searcher);
}
/**
* {@inheritDoc}
*/
public void extractTerms(Set terms) {
contextQuery.extractTerms(terms);
}
/**
* {@inheritDoc}
*/
public Query rewrite(IndexReader reader) throws IOException {
Query cQuery = contextQuery.rewrite(reader);
if (cQuery == contextQuery) {
return this;
} else {
return new ParentAxisQuery(cQuery, nameTest, version, nsMappings);
}
}
/**
* Always returns 'ParentAxisQuery'.
*
* @param field the name of a field.
* @return 'ParentAxisQuery'.
*/
public String toString(String field) {
StringBuffer sb = new StringBuffer();
sb.append("ParentAxisQuery(");
sb.append(contextQuery);
sb.append(", ");
sb.append(nameTest);
sb.append(")");
return sb.toString();
}
//-----------------------< ParentAxisWeight >-------------------------------
/**
* The <code>Weight</code> implementation for this <code>ParentAxisQuery</code>.
*/
private class ParentAxisWeight extends Weight {
/**
* The searcher in use
*/
private final Searcher searcher;
/**
* Creates a new <code>ParentAxisWeight</code> instance using
* <code>searcher</code>.
*
* @param searcher a <code>Searcher</code> instance.
*/
private ParentAxisWeight(Searcher searcher) {
this.searcher = searcher;
}
/**
* Returns this <code>ParentAxisQuery</code>.
*
* @return this <code>ParentAxisQuery</code>.
*/
public Query getQuery() {
return ParentAxisQuery.this;
}
/**
* {@inheritDoc}
*/
public float getValue() {
return 1.0f;
}
/**
* {@inheritDoc}
*/
public float sumOfSquaredWeights() throws IOException {
return 1.0f;
}
/**
* {@inheritDoc}
*/
public void normalize(float norm) {
}
/**
* Creates a scorer for this <code>ParentAxisQuery</code>.
*
* @param reader a reader for accessing the index.
* @return a <code>ParentAxisScorer</code>.
* @throws IOException if an error occurs while reading from the index.
*/
public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder,
boolean topScorer) throws IOException {
contextScorer = contextQuery.weight(searcher).scorer(reader, scoreDocsInOrder, topScorer);
HierarchyResolver resolver = (HierarchyResolver) reader;
return new ParentAxisScorer(searcher.getSimilarity(),
reader, searcher, resolver);
}
/**
* {@inheritDoc}
*/
public Explanation explain(IndexReader reader, int doc) throws IOException {
return new Explanation();
}
}
//--------------------------< ParentAxisScorer >----------------------------
/**
* Implements a <code>Scorer</code> for this <code>ParentAxisQuery</code>.
*/
private class ParentAxisScorer extends Scorer {
/**
* An <code>IndexReader</code> to access the index.
*/
private final IndexReader reader;
/**
* The <code>HierarchyResolver</code> of the index.
*/
private final HierarchyResolver hResolver;
/**
* The searcher instance.
*/
private final Searcher searcher;
/**
* BitSet storing the id's of selected documents
*/
private BitSet hits;
/**
* Map that contains the scores from matching documents from the context
* query. To save memory only scores that are not equal to the score
* value of the first match are put to this map.
* <p/>
* key=[Integer] id of selected document from context query<br>
* value=[Float] score for that document
*/
private final Map<Integer, Float> scores = new HashMap<Integer, Float>();
/**
* The next document id to return
*/
private int nextDoc = -1;
/**
* The score of the first match.
*/
private Float firstScore;
/**
* Creates a new <code>ParentAxisScorer</code>.
*
* @param similarity the <code>Similarity</code> instance to use.
* @param reader for index access.
* @param searcher the index searcher.
* @param resolver the hierarchy resolver.
*/
protected ParentAxisScorer(Similarity similarity,
IndexReader reader,
Searcher searcher,
HierarchyResolver resolver) {
super(similarity);
this.reader = reader;
this.searcher = searcher;
this.hResolver = resolver;
}
@Override
public int nextDoc() throws IOException {
if (nextDoc == NO_MORE_DOCS) {
return nextDoc;
}
calculateParent();
nextDoc = hits.nextSetBit(nextDoc + 1);
if (nextDoc < 0) {
nextDoc = NO_MORE_DOCS;
}
return nextDoc;
}
@Override
public int docID() {
return nextDoc;
}
@Override
public float score() throws IOException {
Float score = scores.get(nextDoc);
if (score == null) {
score = firstScore;
}
return score;
}
@Override
public int advance(int target) throws IOException {
if (nextDoc == NO_MORE_DOCS) {
return nextDoc;
}
calculateParent();
nextDoc = hits.nextSetBit(target);
if (nextDoc < 0) {
nextDoc = NO_MORE_DOCS;
}
return nextDoc;
}
private void calculateParent() throws IOException {
if (hits == null) {
hits = new BitSet(reader.maxDoc());
final IOException[] ex = new IOException[1];
if (contextScorer != null) {
contextScorer.score(new AbstractHitCollector() {
private int[] docs = new int[1];
@Override
protected void collect(int doc, float score) {
try {
docs = hResolver.getParents(doc, docs);
if (docs.length == 1) {
// optimize single value
hits.set(docs[0]);
if (firstScore == null) {
firstScore = score;
} else if (firstScore != score) {
scores.put(doc, score);
}
} else {
for (int docNum : docs) {
hits.set(docNum);
if (firstScore == null) {
firstScore = score;
} else if (firstScore != score) {
scores.put(doc, score);
}
}
}
} catch (IOException e) {
ex[0] = e;
}
}
});
}
if (ex[0] != null) {
throw ex[0];
}
// filter out documents that do not match the name test
if (nameTest != null) {
Query nameQuery = new NameQuery(nameTest, version, nsMappings);
Hits nameHits = new ScorerHits(nameQuery.weight(searcher).scorer(reader, true, false));
for (int i = hits.nextSetBit(0); i >= 0; i = hits.nextSetBit(i + 1)) {
int doc = nameHits.skipTo(i);
if (doc == -1) {
// no more name tests, clear remaining
hits.clear(i, hits.length());
} else {
// assert doc >= i
if (doc > i) {
// clear hits
hits.clear(i, doc);
i = doc;
}
}
}
}
}
}
}
}