/*
* 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 java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import javax.jcr.RepositoryException;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.FieldSelector;
import org.apache.lucene.document.FieldSelectorResult;
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.HitCollector;
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.TermQuery;
import org.apache.lucene.search.Weight;
import org.exoplatform.services.jcr.dataflow.ItemDataConsumer;
import org.exoplatform.services.jcr.datamodel.NodeData;
import org.exoplatform.services.jcr.impl.core.query.LocationStepQueryNode;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.AdaptingHits;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.Hits;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.HitsIntersection;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.ScorerHits;
/**
* Implements a lucene <code>Query</code> which returns the child nodes of the nodes selected by
* another <code>Query</code>.
*/
class ChildAxisQuery extends Query
{
/**
* The item state manager containing persistent item states.
*/
private final ItemDataConsumer itemMgr;
/**
* The context query
*/
private Query contextQuery;
/**
* The nameTest to apply on the child axis, or <code>null</code> if all child nodes should be
* selected.
*/
private final String nameTest;
/**
* The context position for the selected child node, or {@link LocationStepQueryNode#NONE} if no
* position is specified.
*/
private final int position;
/**
* The scorer of the context query
*/
private Scorer contextScorer;
/**
* The scorer of the name test query
*/
private Scorer nameTestScorer;
/**
* Creates a new <code>ChildAxisQuery</code> based on a <code>context</code> query.
*
* @param itemMgr
* the item state manager.
* @param context
* the context for this query.
* @param nameTest
* a name test or <code>null</code> if any child node is selected.
*/
ChildAxisQuery(ItemDataConsumer itemMgr, Query context, String nameTest)
{
this(itemMgr, context, nameTest, LocationStepQueryNode.NONE);
}
/**
* Creates a new <code>ChildAxisQuery</code> based on a <code>context</code> query.
*
* @param itemMgr
* the item state manager.
* @param context
* the context for this query.
* @param nameTest
* a name test or <code>null</code> if any child node is selected.
* @param position
* the context position of the child node to select. If <code>position</code> is
* {@link LocationStepQueryNode#NONE}, the context position of the child node is not
* checked.
*/
ChildAxisQuery(ItemDataConsumer itemMgr, Query context, String nameTest, int position)
{
this.itemMgr = itemMgr;
this.contextQuery = context;
this.nameTest = nameTest;
this.position = position;
}
/**
* Creates a <code>Weight</code> instance for this query.
*
* @param searcher
* the <code>Searcher</code> instance to use.
* @return a <code>ChildAxisWeight</code>.
*/
protected Weight createWeight(Searcher searcher)
{
return new ChildAxisWeight(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 ChildAxisQuery(itemMgr, cQuery, nameTest, position);
}
}
/**
* Always returns 'ChildAxisQuery'.
*
* @param field
* the name of a field.
* @return 'ChildAxisQuery'.
*/
public String toString(String field)
{
return "(ChildAxisQuery " + contextQuery.toString() + " position:" + position + " nameTest:" + nameTest + ")";
}
// -------------------< ChildAxisWeight >------------------------------------
/**
* The <code>Weight</code> implementation for this <code>ChildAxisQuery</code>.
*/
private class ChildAxisWeight implements Weight
{
/**
* The searcher in use
*/
private final Searcher searcher;
/**
* Creates a new <code>ChildAxisWeight</code> instance using <code>searcher</code>.
*
* @param searcher
* a <code>Searcher</code> instance.
*/
private ChildAxisWeight(Searcher searcher)
{
this.searcher = searcher;
}
/**
* Returns this <code>ChildAxisQuery</code>.
*
* @return this <code>ChildAxisQuery</code>.
*/
public Query getQuery()
{
return ChildAxisQuery.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>ChildAxisQuery</code>.
*
* @param reader
* a reader for accessing the index.
* @return a <code>ChildAxisScorer</code>.
* @throws IOException
* if an error occurs while reading from the index.
*/
public Scorer scorer(IndexReader reader) throws IOException
{
contextScorer = contextQuery.weight(searcher).scorer(reader);
if (nameTest != null)
{
nameTestScorer = new TermQuery(new Term(FieldNames.LABEL, nameTest)).weight(searcher).scorer(reader);
}
return new ChildAxisScorer(searcher.getSimilarity(), reader);
}
/**
* {@inheritDoc}
*/
public Explanation explain(IndexReader reader, int doc) throws IOException
{
return new Explanation();
}
}
// ----------------------< ChildAxisScorer >---------------------------------
/**
* Implements a <code>Scorer</code> for this <code>ChildAxisQuery</code>.
*/
private class ChildAxisScorer extends Scorer
{
/**
* An <code>IndexReader</code> to access the index.
*/
private final IndexReader reader;
/**
* The next document id to return
*/
private int nextDoc = -1;
/**
* A <code>Hits</code> instance containing all hits
*/
private Hits hits;
/**
* Creates a new <code>ChildAxisScorer</code>.
*
* @param similarity
* the <code>Similarity</code> instance to use.
* @param reader
* for index access.
*/
protected ChildAxisScorer(Similarity similarity, IndexReader reader)
{
super(similarity);
this.reader = reader;
}
/**
* {@inheritDoc}
*/
public boolean next() throws IOException
{
calculateChildren();
do
{
nextDoc = hits.next();
}
while (nextDoc > -1 && !indexIsValid(nextDoc));
return nextDoc > -1;
}
/**
* {@inheritDoc}
*/
public int doc()
{
return nextDoc;
}
/**
* {@inheritDoc}
*/
public float score() throws IOException
{
return 1.0f;
}
/**
* {@inheritDoc}
*/
public boolean skipTo(int target) throws IOException
{
calculateChildren();
nextDoc = hits.skipTo(target);
while (nextDoc > -1 && !indexIsValid(nextDoc))
next();
return nextDoc > -1;
}
/**
* {@inheritDoc}
*
* @throws UnsupportedOperationException
* this implementation always throws an <code>UnsupportedOperationException</code>.
*/
public Explanation explain(int doc) throws IOException
{
throw new UnsupportedOperationException();
}
private void calculateChildren() throws IOException
{
if (hits == null)
{
// collect all context nodes
List uuids = new ArrayList();
final Hits contextHits = new AdaptingHits();
contextScorer.score(new HitCollector()
{
public void collect(int doc, float score)
{
contextHits.set(doc);
}
});
// read the uuids of the context nodes
int i = contextHits.next();
while (i > -1)
{
String uuid = reader.document(i, new UUIDFieldSelector()).get(FieldNames.UUID);
uuids.add(uuid);
i = contextHits.next();
}
// collect all children of the context nodes
Hits childrenHits = new AdaptingHits();
TermDocs docs = reader.termDocs();
try
{
for (Iterator it = uuids.iterator(); it.hasNext();)
{
docs.seek(new Term(FieldNames.PARENT, (String)it.next()));
while (docs.next())
{
childrenHits.set(docs.doc());
}
}
}
finally
{
docs.close();
}
if (nameTestScorer != null)
{
hits = new HitsIntersection(childrenHits, new ScorerHits(nameTestScorer));
}
else
{
hits = childrenHits;
}
}
}
private boolean indexIsValid(int i) throws IOException
{
if (position != LocationStepQueryNode.NONE)
{
Document node = reader.document(i, new UUIDAndParentFieldSelector());
String parentId = node.get(FieldNames.PARENT);
String id = node.get(FieldNames.UUID);
try
{
NodeData state = (NodeData)itemMgr.getItemData(parentId);
if (state != null)
{
if (nameTest == null)
{
// only select this node if it is the child at
// specified position
if (position == LocationStepQueryNode.LAST)
{
// only select last
List<NodeData> childNodes = itemMgr.getChildNodesData(state);
if (childNodes.size() == 0 || !childNodes.get(childNodes.size() - 1).getIdentifier().equals(id))
{
return false;
}
}
else
{
List<NodeData> childNodes = itemMgr.getChildNodesData(state);
if (position < 1 || childNodes.size() < position
|| !childNodes.get(position - 1).getIdentifier().equals(id))
{
return false;
}
}
}
else
{
// select the node when its index is equal to
// specified position
if (position == LocationStepQueryNode.LAST)
{
// no such child node, probably deleted meanwhile
if (state != null)
{
// only use the last one
List<NodeData> childNodes = itemMgr.getChildNodesData(state);
if (childNodes.size() == 0
|| !childNodes.get(childNodes.size() - 1).getIdentifier().equals(id))
{
return false;
}
}
}
else
{
NodeData nodeData = (NodeData)itemMgr.getItemData(id);
if (nodeData == null)
{
// no such child node, probably has been deleted meanwhile
return false;
}
else
{
if (nodeData.getQPath().getIndex() != position)
{
return false;
}
}
}
}
}
}
catch (RepositoryException e)
{
// ignore this node, probably has been deleted meanwhile
return false;
}
}
return true;
}
}
public class UUIDFieldSelector implements FieldSelector
{
/**
*
*/
private static final long serialVersionUID = 5066344099410213457L;
/**
* {@inheritDoc}
*/
public FieldSelectorResult accept(String fieldName)
{
if (fieldName.equals(FieldNames.UUID))
return FieldSelectorResult.LOAD_AND_BREAK;
return FieldSelectorResult.NO_LOAD;
}
}
public class UUIDAndParentFieldSelector implements FieldSelector
{
/**
*
*/
private static final long serialVersionUID = -7978264122965377378L;
/**
* Accepts {@link FieldNames#UUID} and {@link FieldNames#PARENT}.
*
* @param fieldName the field name to check.
* @return result.
*/
public FieldSelectorResult accept(String fieldName)
{
if (FieldNames.UUID == fieldName)
{
return FieldSelectorResult.LOAD;
}
else if (FieldNames.PARENT == fieldName)
{
return FieldSelectorResult.LOAD;
}
else
{
return FieldSelectorResult.NO_LOAD;
}
}
}
}