/*
* 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.exoplatform.services.jcr.impl.core.query.lucene;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermDocs;
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.Sort;
import org.apache.lucene.search.Weight;
import org.exoplatform.services.jcr.impl.core.SessionImpl;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
/**
* <code>QueryHitsQuery</code> exposes a {@link QueryHits} implementation again
* as a Lucene Query.
*/
public class QueryHitsQuery extends Query implements JcrQuery
{
/**
* The serial version UID
*/
private static final long serialVersionUID = 1792102915934638979L;
/**
* The underlying query hits.
*/
private final QueryHits hits;
/**
* Creates a new query based on {@link QueryHits}.
*
* @param hits the query hits.
*/
public QueryHitsQuery(QueryHits hits)
{
this.hits = hits;
}
/**
* {@inheritDoc}
*/
@Override
public Weight createWeight(Searcher searcher) throws IOException
{
return new QueryHitsQueryWeight(searcher.getSimilarity());
}
/**
* {@inheritDoc}
*/
@Override
public String toString(String field)
{
return "QueryHitsQuery";
}
/**
* {@inheritDoc}
*/
@Override
public void extractTerms(Set<Term> terms)
{
// no terms
}
//-----------------------< JackrabbitQuery >--------------------------------
/**
* {@inheritDoc}
*/
public QueryHits execute(JcrIndexSearcher searcher, SessionImpl session, Sort sort) throws IOException
{
if (sort.getSort().length == 0)
{
return hits;
}
else
{
return null;
}
}
//------------------------< QueryHitsQueryWeight >--------------------------
/**
* The Weight implementation for this query.
*/
public class QueryHitsQueryWeight extends Weight
{
private static final long serialVersionUID = 2350015748527849558L;
/**
* The similarity.
*/
private final Similarity similarity;
/**
* Creates a new weight with the given <code>similarity</code>.
*
* @param similarity the similarity.
*/
public QueryHitsQueryWeight(Similarity similarity)
{
this.similarity = similarity;
}
/**
* {@inheritDoc}
*/
@Override
public Query getQuery()
{
return QueryHitsQuery.this;
}
/**
* {@inheritDoc}
*/
@Override
public float getValue()
{
return 1.0f;
}
/**
* {@inheritDoc}
*/
@Override
public float sumOfSquaredWeights() throws IOException
{
return 1.0f;
}
/**
* {@inheritDoc}
*/
@Override
public void normalize(float norm)
{
}
/**
* {@inheritDoc}
*/
@Override
public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder, boolean topScorer) throws IOException
{
return new QueryHitsQueryScorer(reader, similarity);
}
/**
* {@inheritDoc}
*/
@Override
public Explanation explain(IndexReader reader, int doc) throws IOException
{
return new Explanation();
}
}
//-------------------< QueryHitsQueryScorer >-------------------------------
/**
* the scorer implementation for this query.
*/
public class QueryHitsQueryScorer extends Scorer
{
/**
* Iterator over <code>Integer</code> instances identifying the
* lucene documents. Document numbers are iterated in ascending order.
*/
private final Iterator<Integer> docs;
/**
* Maps <code>Integer</code> document numbers to <code>Float</code>
* scores.
*/
private final Map<Integer, Float> scores = new HashMap<Integer, Float>();
/**
* The current document number.
*/
private Integer currentDoc = null;
/**
* Creates a new scorer.
*
* @param reader the index reader.
* @param similarity the similarity implementation.
* @throws IOException if an error occurs while reading from the index.
*/
protected QueryHitsQueryScorer(IndexReader reader, Similarity similarity) throws IOException
{
super(similarity);
ScoreNode node;
Set<Integer> sortedDocs = new TreeSet<Integer>();
try
{
while ((node = hits.nextScoreNode()) != null)
{
String uuid = node.getNodeId();
Term id = new Term(FieldNames.UUID, uuid);
TermDocs tDocs = reader.termDocs(id);
try
{
if (tDocs.next())
{
Integer doc = new Integer(tDocs.doc());
sortedDocs.add(doc);
scores.put(doc, new Float(node.getScore()));
}
}
finally
{
tDocs.close();
}
}
}
finally
{
hits.close();
}
docs = sortedDocs.iterator();
}
/**
* {@inheritDoc}
*/
@Override
public int nextDoc() throws IOException
{
if (currentDoc == NO_MORE_DOCS)
{
return currentDoc;
}
currentDoc = docs.hasNext() ? docs.next() : NO_MORE_DOCS;
return currentDoc;
}
/**
* {@inheritDoc}
*/
@Override
public int docID()
{
return currentDoc == null ? -1 : currentDoc;
}
/**
* {@inheritDoc}
*/
@Override
public float score() throws IOException
{
return scores.get(currentDoc).floatValue();
}
/**
* {@inheritDoc}
*/
@Override
public int advance(int target) throws IOException
{
if (currentDoc == NO_MORE_DOCS)
{
return currentDoc;
}
do
{
if (nextDoc() == NO_MORE_DOCS)
{
return NO_MORE_DOCS;
}
}
while (target > docID());
return docID();
}
}
}