/*
* 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.document.Document;
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.dataflow.ItemDataConsumer;
import org.exoplatform.services.jcr.datamodel.InternalQName;
import org.exoplatform.services.jcr.datamodel.NodeData;
import org.exoplatform.services.jcr.impl.core.SessionImpl;
import org.exoplatform.services.jcr.impl.core.query.LocationStepQueryNode;
import org.exoplatform.services.jcr.impl.core.query.lucene.hits.AbstractHitCollector;
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.ScorerHits;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.jcr.RepositoryException;
/**
* Implements a lucene <code>Query</code> which returns the child nodes of the
* nodes selected by another <code>Query</code>.
*/
class ChildAxisQuery extends Query implements JcrQuery
{
/**
* The logger instance for this class.
*/
private static final Logger LOG = LoggerFactory.getLogger("exo.jcr.component.core.ChildAxisQuery");
/**
* Threshold when children calculation is switched to
* {@link HierarchyResolvingChildrenCalculator}.
*/
private static int CONTEXT_SIZE_THRESHOLD = 10;
/**
* 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 InternalQName nameTest;
/**
* The context position for the selected child node, or
* {@link LocationStepQueryNode#NONE} if no position is specified.
*/
private final int position;
/**
* 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;
/**
* 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.
* @param version the index format version.
* @param nsMappings the internal namespace mappings.
*/
ChildAxisQuery(ItemDataConsumer itemMgr, Query context, InternalQName nameTest, IndexFormatVersion version,
NamespaceMappings nsMappings)
{
this(itemMgr, context, nameTest, LocationStepQueryNode.NONE, version, nsMappings);
}
/**
* 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.
* @param version the index format version.
* @param nsMapping the internal namespace mappings.
*/
ChildAxisQuery(ItemDataConsumer itemMgr, Query context, InternalQName nameTest, int position,
IndexFormatVersion version, NamespaceMappings nsMapping)
{
this.itemMgr = itemMgr;
this.contextQuery = context;
this.nameTest = nameTest;
this.position = position;
this.version = version;
this.nsMappings = nsMapping;
}
/**
* @return the context query of this child axis query.
*/
Query getContextQuery()
{
return contextQuery;
}
/**
* @return <code>true</code> if this child axis query matches any child
* node; <code>false</code> otherwise.
*/
boolean matchesAnyChildNode()
{
return nameTest == null && position == LocationStepQueryNode.NONE;
}
/**
* @return the name test or <code>null</code> if none was specified.
*/
InternalQName getNameTest()
{
return nameTest;
}
/**
* @return the position check or {@link LocationStepQueryNode#NONE} is none
* was specified.
*/
int getPosition()
{
return position;
}
/**
* Creates a <code>Weight</code> instance for this query.
*
* @param searcher the <code>Searcher</code> instance to use.
* @return a <code>ChildAxisWeight</code>.
*/
@Override
public Weight createWeight(Searcher searcher)
{
return new ChildAxisWeight(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);
// only try to compact if no position is specified
if (position == LocationStepQueryNode.NONE)
{
if (cQuery instanceof DescendantSelfAxisQuery)
{
DescendantSelfAxisQuery dsaq = (DescendantSelfAxisQuery)cQuery;
if (dsaq.subQueryMatchesAll())
{
Query sub;
if (nameTest == null)
{
sub = new MatchAllDocsQuery();
}
else
{
sub = new NameQuery(nameTest, version, nsMappings);
}
return new DescendantSelfAxisQuery(dsaq.getContextQuery(), sub, dsaq.getMinLevels() + 1).rewrite(reader);
}
}
}
// if we get here we could not compact the query
if (cQuery == contextQuery) // NOSONAR
{
return this;
}
else
{
return new ChildAxisQuery(itemMgr, cQuery, nameTest, position, version, nsMappings);
}
}
/**
* {@inheritDoc}
*/
@Override
public String toString(String field)
{
StringBuffer sb = new StringBuffer();
sb.append("ChildAxisQuery(");
sb.append(contextQuery);
sb.append(", ");
sb.append(nameTest.getAsString());
if (position != LocationStepQueryNode.NONE)
{
sb.append(", ");
sb.append(position);
}
sb.append(")");
return sb.toString();
}
//-------------------< JackrabbitQuery >------------------------------------
/**
* {@inheritDoc}
*/
public QueryHits execute(JcrIndexSearcher searcher, SessionImpl session, Sort sort) throws IOException
{
if (sort.getSort().length == 0 && matchesAnyChildNode())
{
Query context = getContextQuery();
return new ChildNodesQueryHits(searcher.evaluate(context), session);
}
else
{
return null;
}
}
//-------------------< ChildAxisWeight >------------------------------------
/**
* The <code>Weight</code> implementation for this <code>ChildAxisQuery</code>.
*/
private class ChildAxisWeight extends 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>.
*/
@Override
public Query getQuery()
{
return ChildAxisQuery.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>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.
*/
@Override
public Scorer scorer(IndexReader reader, boolean scoreDocsInOrder, boolean topScorer) throws IOException
{
contextScorer = contextQuery.weight(searcher).scorer(reader, scoreDocsInOrder, topScorer);
if (nameTest != null)
{
nameTestScorer =
new NameQuery(nameTest, version, nsMappings).weight(searcher)
.scorer(reader, scoreDocsInOrder, topScorer);
}
return new ChildAxisScorer(searcher.getSimilarity(), reader, (HierarchyResolver)reader);
}
/**
* {@inheritDoc}
*/
@Override
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 <code>HierarchyResolver</code> of the index.
*/
private final HierarchyResolver hResolver;
/**
* 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.
* @param hResolver the hierarchy resolver of <code>reader</code>.
*/
protected ChildAxisScorer(Similarity similarity, IndexReader reader, HierarchyResolver hResolver)
{
super(similarity);
this.reader = reader;
this.hResolver = hResolver;
}
/**
* {@inheritDoc}
*/
@Override
public boolean next() throws IOException
{
calculateChildren();
do
{
nextDoc = hits.next();
}
while (nextDoc > -1 && !indexIsValid(nextDoc));
return nextDoc > -1;
}
/**
* {@inheritDoc}
*/
@Override
public int doc()
{
return nextDoc;
}
/**
* {@inheritDoc}
*/
@Override
public float score() throws IOException
{
return 1.0f;
}
/**
* {@inheritDoc}
*/
@Override
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>.
*/
@Override
public Explanation explain(int doc) throws IOException
{
throw new UnsupportedOperationException();
}
private void calculateChildren() throws IOException
{
if (hits == null)
{
final ChildrenCalculator[] calc = new ChildrenCalculator[1];
if (nameTestScorer == null)
{
// always use simple in that case
calc[0] = new SimpleChildrenCalculator(reader, hResolver);
contextScorer.score(new AbstractHitCollector()
{
@Override
public void collect(int doc, float score)
{
calc[0].collectContextHit(doc);
}
});
}
else
{
// start simple but switch once threshold is reached
calc[0] = new SimpleChildrenCalculator(reader, hResolver);
contextScorer.score(new AbstractHitCollector()
{
private List docIds = new ArrayList();
@Override
public void collect(int doc, float score)
{
calc[0].collectContextHit(doc);
if (docIds != null)
{
docIds.add(new Integer(doc));
if (docIds.size() > CONTEXT_SIZE_THRESHOLD)
{
// switch
calc[0] = new HierarchyResolvingChildrenCalculator(reader, hResolver);
for (Iterator it = docIds.iterator(); it.hasNext();)
{
calc[0].collectContextHit(((Integer)it.next()).intValue());
}
// indicate that we switched
docIds = null;
}
}
}
});
}
hits = calc[0].getHits();
}
}
private boolean indexIsValid(int i) throws IOException
{
if (position != LocationStepQueryNode.NONE)
{
Document node = reader.document(i, FieldSelectors.UUID_AND_PARENT_AND_INDEX);
String parentId = node.get(FieldNames.PARENT);
String id = node.get(FieldNames.UUID);
try
{
if (nameTest == null)
{
NodeData state = (NodeData)itemMgr.getItemData(parentId);
// 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)
{
NodeData state = (NodeData)itemMgr.getItemData(parentId);
// only select last
if (state == null)
{
// no such child node, probably deleted meanwhile
return false;
}
else
{
// 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 if (version.getVersion() >= IndexFormatVersion.V4.getVersion())
{
if (Integer.valueOf(node.get(FieldNames.INDEX)) != position)
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;
}
}
/**
* Base class to calculate the children for a context query.
*/
private abstract class ChildrenCalculator
{
/**
* The current index reader.
*/
protected final IndexReader reader;
/**
* The current hierarchy resolver.
*/
protected final HierarchyResolver hResolver;
/**
* Creates a new children calculator with the given index reader and
* hierarchy resolver.
*
* @param reader the current index reader.
* @param hResolver the current hierarchy resolver.
*/
public ChildrenCalculator(IndexReader reader, HierarchyResolver hResolver)
{
this.reader = reader;
this.hResolver = hResolver;
}
/**
* Collects a context hit.
*
* @param doc the lucene document number of the context hit.
*/
protected abstract void collectContextHit(int doc);
/**
* @return the hits that contains the children.
* @throws IOException if an error occurs while reading from the index.
*/
public abstract Hits getHits() throws IOException;
}
/**
* An implementation of a children calculator using the item state manager.
*/
private final class SimpleChildrenCalculator extends ChildrenCalculator
{
/**
* The context hits.
*/
private final Hits contextHits = new AdaptingHits();
/**
* Creates a new simple children calculator.
*
* @param reader the current index reader.
* @param hResolver the current hierarchy resolver.
*/
public SimpleChildrenCalculator(IndexReader reader, HierarchyResolver hResolver)
{
super(reader, hResolver);
}
/**
* {@inheritDoc}
*/
@Override
protected void collectContextHit(int doc)
{
contextHits.set(doc);
}
/**
* {@inheritDoc}
*/
@Override
public Hits getHits() throws IOException
{
// read the uuids of the context nodes
Map uuids = new HashMap();
for (int i = contextHits.next(); i > -1; i = contextHits.next())
{
String uuid = reader.document(i, FieldSelectors.UUID).get(FieldNames.UUID);
uuids.put(new Integer(i), uuid);
}
// get child node entries for each hit
Hits childrenHits = new AdaptingHits();
for (Iterator it = uuids.values().iterator(); it.hasNext();)
{
String uuid = (String)it.next();
try
{
if (nameTest != null && version.getVersion() >= IndexFormatVersion.V4.getVersion())
{
StringBuilder path = new StringBuilder(256);
path.append(uuid == null ? "" : uuid).append('/').append(nameTest.getAsString());
TermDocs docs = reader.termDocs(new Term(FieldNames.PATH, path.toString()));
try
{
while (docs.next())
{
childrenHits.set(docs.doc());
}
}
finally
{
docs.close();
}
}
else
{
long time = System.currentTimeMillis();
NodeData state = (NodeData)itemMgr.getItemData(uuid);
time = System.currentTimeMillis() - time;
LOG.debug("got NodeState with id {} in {} ms.", uuid, new Long(time));
Iterator<NodeData> entries;
if (nameTest != null)
{
List<NodeData> childs = itemMgr.getChildNodesData(state);
List<NodeData> datas = new ArrayList<NodeData>();
if (childs != null)
{
for (NodeData nodeData : childs)
{
if (nameTest.equals(nodeData.getQPath().getName()))
datas.add(nodeData);
}
}
entries = datas.iterator();
}
else
{
// get all children
entries = itemMgr.getChildNodesData(state).iterator();
}
while (entries.hasNext())
{
String childId = entries.next().getIdentifier();
Term uuidTerm = new Term(FieldNames.UUID, childId);
TermDocs docs = reader.termDocs(uuidTerm);
try
{
if (docs.next())
{
childrenHits.set(docs.doc());
}
}
finally
{
docs.close();
}
}
}
}
catch (RepositoryException e)
{
if (LOG.isTraceEnabled())
{
LOG.trace("An exception occurred: " + e.getMessage());
}
}
}
return childrenHits;
}
}
/**
* An implementation of a children calculator that uses the hierarchy
* resolver. This implementation requires that
* {@link ChildAxisQuery#nameTestScorer} is non null.
*/
private final class HierarchyResolvingChildrenCalculator extends ChildrenCalculator
{
/**
* The document numbers of the context hits.
*/
private final Set docIds = new HashSet();
/**
* Creates a new hierarchy resolving children calculator.
*
* @param reader the current index reader.
* @param hResolver the current hierarchy resolver.
*/
public HierarchyResolvingChildrenCalculator(IndexReader reader, HierarchyResolver hResolver)
{
super(reader, hResolver);
}
/**
* {@inheritDoc}
*/
@Override
protected void collectContextHit(int doc)
{
docIds.add(new Integer(doc));
}
/**
* {@inheritDoc}
*/
@Override
public Hits getHits() throws IOException
{
long time = 0;
if (LOG.isDebugEnabled())
{
time = System.currentTimeMillis();
}
Hits childrenHits = new AdaptingHits();
Hits nameHits = new ScorerHits(nameTestScorer);
int[] docs = new int[1];
for (int h = nameHits.next(); h > -1; h = nameHits.next())
{
docs = hResolver.getParents(h, docs);
if (docs.length == 1)
{
// optimize single value
if (docIds.contains(new Integer(docs[0])))
{
childrenHits.set(h);
}
}
else
{
for (int i = 0; i < docs.length; i++)
{
if (docIds.contains(new Integer(docs[i])))
{
childrenHits.set(h);
}
}
}
}
if (LOG.isDebugEnabled())
{
time = System.currentTimeMillis() - time;
LOG.debug("Filtered hits in {} ms.", new Long(time));
}
return childrenHits;
}
}
}