/*
* 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.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 org.exoplatform.services.jcr.datamodel.InternalQName;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.AbstractHitCollector;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.Hits;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.ScorerHits;
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.
*/
class ParentAxisQuery extends Query
{
/**
* Default score is 1.0f.
*/
private static final Float DEFAULT_SCORE = new Float(1.0f);
/**
* 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 InternalQName 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, InternalQName 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>.
*/
@Override
public Weight createWeight(Searcher searcher)
{
return new ParentAxisWeight(searcher);
}
/**
* {@inheritDoc}
*/
@Override
public void extractTerms(Set terms)
{
contextQuery.extractTerms(terms);
}
/**
* {@inheritDoc}
*/
@Override
public Query rewrite(IndexReader reader) throws IOException
{
Query cQuery = contextQuery.rewrite(reader);
if (cQuery == contextQuery) // NOSONAR
{
return this;
}
else
{
return new ParentAxisQuery(cQuery, nameTest, version, nsMappings);
}
}
/**
* Always returns 'ParentAxisQuery'.
*
* @param field the name of a field.
* @return 'ParentAxisQuery'.
*/
@Override
public String toString(String field)
{
return "ParentAxisQuery " + "nameTest=" + (nameTest != null ? nameTest.toString() : "null") + " contextQuery="
+ contextQuery.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>.
*/
@Override
public Query getQuery()
{
return ParentAxisQuery.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)
{
}
/**
* 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.
*/
@Override
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}
*/
@Override
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 1.0f 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 scores = new HashMap();
/**
* The next document id to return
*/
private int nextDoc = -1;
/**
* 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;
}
/**
* {@inheritDoc}
*/
@Override
public boolean next() throws IOException
{
calculateParent();
nextDoc = hits.nextSetBit(nextDoc + 1);
return nextDoc > -1;
}
/**
* {@inheritDoc}
*/
@Override
public int doc()
{
return nextDoc;
}
/**
* {@inheritDoc}
*/
@Override
public float score() throws IOException
{
Float score = (Float)scores.get(new Integer(nextDoc));
if (score == null)
{
score = DEFAULT_SCORE;
}
return score.floatValue();
}
/**
* {@inheritDoc}
*/
@Override
public boolean skipTo(int target) throws IOException
{
calculateParent();
nextDoc = hits.nextSetBit(target);
return nextDoc > -1;
}
/**
* {@inheritDoc}
*
* @throws UnsupportedOperationException this implementation always
* throws an <code>UnsupportedOperationException</code>.
*/
@Override
public Explanation explain(int doc) throws IOException
{
throw new UnsupportedOperationException();
}
private void calculateParent() throws IOException
{
if (hits == null)
{
hits = new BitSet(reader.maxDoc());
final IOException[] ex = new IOException[1];
contextScorer.score(new AbstractHitCollector()
{
private int[] docs = new int[1];
@Override
public void collect(int doc, float score)
{
try
{
docs = hResolver.getParents(doc, docs);
if (docs.length == 1)
{
// optimize single value
hits.set(docs[0]);
if (score != DEFAULT_SCORE.floatValue())
{
scores.put(new Integer(docs[0]), new Float(score));
}
}
else
{
for (int i = 0; i < docs.length; i++)
{
hits.set(docs[i]);
if (score != DEFAULT_SCORE.floatValue())
{
scores.put(new Integer(docs[i]), new Float(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;
}
}
}
}
}
}
}
}