/*
* 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.apache.jackrabbit.oak.jcr.query;
import java.util.Arrays;
import java.util.Iterator;
import java.util.NoSuchElementException;
import javax.annotation.CheckForNull;
import javax.jcr.NodeIterator;
import javax.jcr.RepositoryException;
import javax.jcr.Value;
import javax.jcr.query.QueryResult;
import javax.jcr.query.RowIterator;
import org.apache.jackrabbit.commons.iterator.NodeIteratorAdapter;
import org.apache.jackrabbit.commons.iterator.RowIteratorAdapter;
import org.apache.jackrabbit.oak.api.PropertyValue;
import org.apache.jackrabbit.oak.api.Result;
import org.apache.jackrabbit.oak.api.ResultRow;
import org.apache.jackrabbit.oak.commons.PathUtils;
import org.apache.jackrabbit.oak.jcr.session.NodeImpl;
import org.apache.jackrabbit.oak.jcr.session.SessionContext;
import org.apache.jackrabbit.oak.jcr.delegate.NodeDelegate;
import org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate;
import org.apache.jackrabbit.oak.plugins.value.ValueFactoryImpl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The implementation of the corresponding JCR interface.
*/
public class QueryResultImpl implements QueryResult {
static final Logger LOG = LoggerFactory.getLogger(QueryResultImpl.class);
/**
* The minimum number of rows / nodes to pre-fetch.
*/
private static final int PREFETCH_MIN = 20;
/**
* The maximum number of rows / nodes to pre-fetch.
*/
private static final int PREFETCH_MAX = 100;
/**
* The maximum number of milliseconds to prefetch rows / nodes.
*/
private static final int PREFETCH_TIMEOUT = 100;
final Result result;
private final SessionContext sessionContext;
private final SessionDelegate sessionDelegate;
private final String pathFilter;
public QueryResultImpl(SessionContext sessionContext, Result result) {
this.sessionContext = sessionContext;
this.sessionDelegate = sessionContext.getSessionDelegate();
this.result = result;
// TODO the path currently contains the workspace name
// TODO filter in oak-core once we support workspaces there
pathFilter = "/";
}
@Override
public String[] getColumnNames() throws RepositoryException {
return result.getColumnNames();
}
@Override
public String[] getSelectorNames() {
return result.getSelectorNames();
}
boolean includeRow(String path) {
if (path == null) {
// a row without path (explain,...)
return true;
}
if (PathUtils.isAncestor(pathFilter, path) || pathFilter.equals(path)) {
// a row within this workspace
return true;
}
return false;
}
@Override
public RowIterator getRows() throws RepositoryException {
Iterator<RowImpl> rowIterator = new Iterator<RowImpl>() {
private final Iterator<? extends ResultRow> it = result.getRows().iterator();
private final String pathSelector;
private RowImpl current;
{
String[] columnSelectorNames = result.getColumnSelectorNames();
if (columnSelectorNames.length == 1) {
pathSelector = columnSelectorNames[0];
} else {
pathSelector = null;
}
fetch();
}
private void fetch() {
current = null;
while (it.hasNext()) {
ResultRow r = it.next();
boolean include = true;
for (String s : getSelectorNames()) {
String path = r.getPath(s);
if (!includeRow(path)) {
include = false;
break;
}
}
if (include) {
current = new RowImpl(QueryResultImpl.this, r, pathSelector);
return;
}
}
}
@Override
public boolean hasNext() {
return current != null;
}
@Override
public RowImpl next() {
if (current == null) {
throw new NoSuchElementException();
}
RowImpl r = current;
fetch();
return r;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
final PrefetchIterator<RowImpl> prefIt = new PrefetchIterator<RowImpl>(
rowIterator,
PREFETCH_MIN, PREFETCH_TIMEOUT, PREFETCH_MAX,
result.getSize());
return new RowIteratorAdapter(prefIt) {
@Override
public long getSize() {
return prefIt.size();
}
};
}
@CheckForNull
NodeImpl<? extends NodeDelegate> getNode(String path) throws RepositoryException {
if (path == null) {
return null;
}
NodeDelegate d = sessionDelegate.getNode(path);
return d == null ? null : NodeImpl.createNode(d, sessionContext);
}
String getLocalPath(String path) {
if (path == null) {
return null;
}
return PathUtils.concat("/", PathUtils.relativize(pathFilter, path));
}
@Override
public NodeIterator getNodes() throws RepositoryException {
String[] columnSelectorNames = result.getColumnSelectorNames();
if (columnSelectorNames.length != 1) {
throw new RepositoryException("Query contains more than one selector: " +
Arrays.toString(columnSelectorNames));
}
final String selectorName = columnSelectorNames[0];
if (selectorName == null) {
throw new RepositoryException("Query does not contain a selector: " +
Arrays.toString(columnSelectorNames));
}
Iterator<NodeImpl<? extends NodeDelegate>> nodeIterator = new Iterator<NodeImpl<? extends NodeDelegate>>() {
private final Iterator<? extends ResultRow> it = result.getRows().iterator();
private NodeImpl<? extends NodeDelegate> current;
{
fetch();
}
private void fetch() {
current = null;
while (it.hasNext()) {
ResultRow r = it.next();
String path = r.getPath(selectorName);
if (includeRow(path)) {
try {
current = getNode(getLocalPath(path));
break;
} catch (RepositoryException e) {
LOG.warn("Unable to fetch result node for path " + path, e);
}
}
}
}
@Override
public boolean hasNext() {
return current != null;
}
@Override
public NodeImpl<? extends NodeDelegate> next() {
if (current == null) {
throw new NoSuchElementException();
}
NodeImpl<? extends NodeDelegate> n = current;
fetch();
return n;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
final PrefetchIterator<NodeImpl<? extends NodeDelegate>> prefIt = new PrefetchIterator<NodeImpl<? extends NodeDelegate>>(
nodeIterator,
PREFETCH_MIN, PREFETCH_TIMEOUT, PREFETCH_MAX,
result.getSize());
return new NodeIteratorAdapter(prefIt) {
@Override
public long getSize() {
return prefIt.size();
}
};
}
Value createValue(PropertyValue value) {
if (value == null) {
return null;
}
return ValueFactoryImpl.createValue(value, sessionContext);
}
}