/*
* 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.plugins.document.mongo;
import java.io.Closeable;
import java.util.Queue;
import com.google.common.collect.AbstractIterator;
import com.google.common.collect.Queues;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.QueryBuilder;
import com.mongodb.ReadPreference;
import org.apache.jackrabbit.oak.api.Blob;
import org.apache.jackrabbit.oak.plugins.document.BlobCollector;
import org.apache.jackrabbit.oak.plugins.document.Collection;
import org.apache.jackrabbit.oak.plugins.document.DocumentNodeStore;
import org.apache.jackrabbit.oak.plugins.document.NodeDocument;
public class MongoBlobReferenceIterator extends AbstractIterator<Blob> implements Closeable {
private final MongoDocumentStore documentStore;
private final BlobCollector blobCollector;
private final Queue<Blob> blobs = Queues.newArrayDeque();
private DBCursor cursor;
public MongoBlobReferenceIterator(DocumentNodeStore nodeStore,
MongoDocumentStore documentStore) {
this.documentStore = documentStore;
this.blobCollector = new BlobCollector(nodeStore);
}
@Override
protected Blob computeNext() {
if (blobs.isEmpty()) {
loadBatch();
}
if (!blobs.isEmpty()) {
return blobs.remove();
}
return endOfData();
}
private void loadBatch() {
initializeCursor();
//Some node which have the '_bin' flag set might not have any binaries in it
//so move forward if blobs is still empty and cursor has more elements
while (cursor.hasNext() && blobs.isEmpty()) {
collectBinaries(documentStore.convertFromDBObject(Collection.NODES, cursor.next()));
}
}
private void collectBinaries(NodeDocument nodeDocument) {
blobCollector.collect(nodeDocument, blobs);
}
private void initializeCursor() {
if (cursor == null) {
DBObject query = QueryBuilder.start(NodeDocument.HAS_BINARY_FLAG)
.is(NodeDocument.HAS_BINARY_VAL)
.get();
//TODO It currently prefers secondary. Would that be Ok?
cursor = getNodeCollection().find(query).setReadPreference(ReadPreference.secondaryPreferred());
}
}
private DBCollection getNodeCollection() {
return documentStore.getDBCollection(Collection.NODES);
}
@Override
public void close() {
if (cursor != null) {
cursor.close();
}
}
}