/*
* 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.commons.collections.iterators.IteratorChain;
import org.exoplatform.services.jcr.datamodel.NodeData;
import org.exoplatform.services.jcr.impl.core.NodeImpl;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import javax.jcr.Node;
import javax.jcr.NodeIterator;
import javax.jcr.RepositoryException;
/**
* <code>NodeTraversingQueryHits</code> implements query hits that traverse
* a node hierarchy.
*/
public class NodeTraversingQueryHits extends AbstractQueryHits
{
private static final Log LOG = ExoLogger.getLogger("exo.jcr.component.core.NodeTraversingQueryHits");
/**
* The nodes to traverse.
*/
private final Iterator<Node> nodes;
private IndexingConfiguration indexConfig;
/**
* Creates query hits that consist of the nodes that are traversed from a
* given <code>start</code> node.
*
* @param start the start node of the traversal.
* @param includeStart whether to include the start node in the result.
*/
public NodeTraversingQueryHits(Node start, boolean includeStart, IndexingConfiguration indexConfig) {
this(start, includeStart, Integer.MAX_VALUE, indexConfig);
}
/**
* Creates query hits that consist of the nodes that are traversed from a
* given <code>start</code> node.
*
* @param start the start node of the traversal.
* @param includeStart whether to include the start node in the result.
* @param maxDepth the maximum depth of nodes to traverse.
*/
public NodeTraversingQueryHits(Node start,
boolean includeStart,
int maxDepth,
IndexingConfiguration indexConfig) {
this.nodes = new TraversingNodeIterator(start, maxDepth);
this.indexConfig = indexConfig;
if (!includeStart) {
nodes.next();
}
}
/**
* {@inheritDoc}
*/
public ScoreNode nextScoreNode() throws IOException {
if (nodes.hasNext()) {
NodeImpl n = (NodeImpl) nodes.next();
return new ScoreNode(n.getData().getIdentifier(), 1.0f);
} else {
return null;
}
}
/**
* Implements a node iterator that traverses a node tree in document
* order.
*/
private class TraversingNodeIterator implements Iterator<Node> {
/**
* The current <code>Node</code>, which acts as the starting point for
* the traversal.
*/
private final Node currentNode;
/**
* The maximum depth of the traversal.
*/
private final int maxDepth;
/**
* The chain of iterators which includes the iterators of the children
* of the current node.
*/
private Iterator<Node> selfAndChildren;
/**
* Creates a <code>TraversingNodeIterator</code>.
*
* @param start the node from where to start the traversal.
* @param maxDepth the maximum depth of nodes to traverse.
*/
TraversingNodeIterator(Node start, int maxDepth) {
if (maxDepth < 0) {
throw new IllegalArgumentException("maxDepth must be >= 0");
}
currentNode = start;
this.maxDepth = maxDepth;
}
/**
* @exception UnsupportedOperationException always.
*/
public void remove() {
throw new UnsupportedOperationException("remove");
}
/**
* {@inheritDoc}
*/
public boolean hasNext() {
init();
return selfAndChildren.hasNext();
}
/**
* {@inheritDoc}
*/
public Node next() {
init();
NodeImpl n = (NodeImpl) selfAndChildren.next();
return n;
}
/**
* Initializes the iterator chain once.
*/
@SuppressWarnings("unchecked")
private void init()
{
if (selfAndChildren == null)
{
List<Iterator<Node>> allIterators = new ArrayList<Iterator<Node>>();
Iterator<Node> current = Collections.singletonList(currentNode).iterator();
allIterators.add(current);
if (maxDepth == 0)
{
// only current node
}
else if (maxDepth == 1)
{
try
{
allIterators.add(currentNode.getNodes());
}
catch (RepositoryException e)
{
if (LOG.isTraceEnabled())
{
LOG.trace("An exception occurred: " + e.getMessage());
}
}
}
else
{
// create new TraversingNodeIterator for each child
try
{
if (indexConfig == null || !indexConfig.isExcluded((NodeData)((NodeImpl)currentNode).getData()))
{
NodeIterator children = currentNode.getNodes();
while (children.hasNext())
{
NodeImpl node = (NodeImpl)children.nextNode();
if (indexConfig == null || !indexConfig.isExcluded((NodeData)node.getData()))
{
allIterators.add(new TraversingNodeIterator(node, maxDepth - 1));
}
}
}
}
catch (RepositoryException e)
{
if (LOG.isTraceEnabled())
{
LOG.trace("An exception occurred: " + e.getMessage());
}
}
}
selfAndChildren = new IteratorChain(allIterators);
}
}
}
}