Java tutorial
/* * 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 javax.annotation.Nonnull; import static com.google.common.collect.Iterables.transform; import static com.mongodb.QueryBuilder.start; import com.google.common.base.Function; import com.mongodb.BasicDBObject; 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.plugins.document.ClusterNodeInfo; import org.apache.jackrabbit.oak.plugins.document.Collection; import org.apache.jackrabbit.oak.plugins.document.MissingLastRevSeeker; import org.apache.jackrabbit.oak.plugins.document.NodeDocument; import org.apache.jackrabbit.oak.plugins.document.util.CloseableIterable; import org.apache.jackrabbit.oak.stats.Clock; /** * Mongo specific version of MissingLastRevSeeker which uses mongo queries * to fetch candidates which may have missed '_lastRev' updates. * * Uses a time range to find documents modified during that interval. */ public class MongoMissingLastRevSeeker extends MissingLastRevSeeker { private final MongoDocumentStore store; public MongoMissingLastRevSeeker(MongoDocumentStore store, Clock clock) { super(store, clock); this.store = store; } @Override @Nonnull public CloseableIterable<NodeDocument> getCandidates(final long startTime) { DBObject query = start(NodeDocument.MODIFIED_IN_SECS) .greaterThanEquals(NodeDocument.getModifiedInSecs(startTime)).get(); DBObject sortFields = new BasicDBObject(NodeDocument.MODIFIED_IN_SECS, -1); DBCursor cursor = getNodeCollection().find(query).sort(sortFields) .setReadPreference(ReadPreference.primary()); return CloseableIterable.wrap(transform(cursor, new Function<DBObject, NodeDocument>() { @Override public NodeDocument apply(DBObject input) { return store.convertFromDBObject(Collection.NODES, input); } }), cursor); } @Override public boolean isRecoveryNeeded() { QueryBuilder query = start(ClusterNodeInfo.STATE).is(ClusterNodeInfo.ClusterNodeState.ACTIVE.name()) .put(ClusterNodeInfo.LEASE_END_KEY).lessThan(clock.getTime()); return getClusterNodeCollection().findOne(query.get()) != null; } private DBCollection getNodeCollection() { return store.getDBCollection(Collection.NODES); } private DBCollection getClusterNodeCollection() { return store.getDBCollection(Collection.CLUSTER_NODES); } }