/**
* 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.waveprotocol.box.server.persistence.mongodb;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.mongodb.DB;
import com.mongodb.Mongo;
import com.mongodb.MongoClient;
import com.mongodb.MongoException;
import org.waveprotocol.box.server.persistence.PersistenceStartException;
import org.waveprotocol.wave.util.logging.Log;
import java.net.UnknownHostException;
/**
* Class to lazily setup and manage the MongoDb connection.
*
* @author ljvderijk@google.com (Lennard de Rijk)
*
*/
public class MongoDbProvider {
private static final Log LOG = Log.get(MongoDbProvider.class);
private String dbHost;
private String dbPort;
private String dbName;
/**
* Our {@link MongoClient} instance, should be accessed by getMongo unless during
* start().
*/
private Mongo mongo;
/**
* Lazily instantiated {@link MongoDbStore}.
*/
private MongoDbStore mongoDbStore;
/**
* Separated store for Deltas {@link MongoDbDeltaStore}
*/
private MongoDbDeltaStore mongoDbDeltaStore;
/** Stores whether we have successfully setup a live {@link Mongo} instance. */
private boolean isRunning;
/**
* Constructs a new empty {@link MongoDbProvider}.
*/
public MongoDbProvider(String dbHost, String dbPort, String dbName) {
this.dbHost = dbHost;
this.dbPort = dbPort;
this.dbName = dbName;
}
/**
* Starts the {@link Mongo} instance and explicitly checks whether it is
* actually alive.
*
* @throws PersistenceStartException if we can't make a connection to MongoDb.
*/
private void start() {
Preconditions.checkState(!isRunning(), "Can't start after a connection has been established");
String host = dbHost;
int port = Integer.parseInt(dbPort);
try {
// New MongoDB Client, see http://docs.mongodb.org/manual/release-notes/drivers-write-concern/
mongo = new MongoClient(host, port);
} catch (UnknownHostException e) {
throw new PersistenceStartException("Unable to resolve the MongoDb hostname", e);
}
try {
// Check to see if we are alive
mongo.getDB(dbName).command("ping");
} catch (MongoException e) {
throw new PersistenceStartException("Can't ping MongoDb", e);
}
isRunning = true;
LOG.info("Started MongoDb persistence");
}
/**
* Returns the {@link DB} with the name that is specified in the properties
* file.
*/
private DB getDatabase() {
return getDatabaseForName(dbName);
}
/**
* Returns a {@link DB} instance for the database with the given name
*
* @param name the name of the database
*/
@VisibleForTesting
DB getDatabaseForName(String name) {
return getMongo().getDB(name);
}
/**
* Return the {@link Mongo} instance that we are managing.
*/
private Mongo getMongo() {
if (!isRunning) {
start();
}
return mongo;
}
/**
* Returns true iff the {@link MongoDbProvider} is running.
*/
public boolean isRunning() {
return isRunning;
}
/**
* Returns a {@link MongoDbStore} instance created from the settings in this
* provider.
*/
public MongoDbStore provideMongoDbStore() {
if (mongoDbStore == null) {
mongoDbStore = new MongoDbStore(getDatabase());
}
return mongoDbStore;
}
/**
* Returns a {@link MongoDbDeltaStore} instance created from the settings in this
* provider.
*/
public MongoDbDeltaStore provideMongoDbDeltaStore() {
if (mongoDbDeltaStore == null) {
mongoDbDeltaStore = new MongoDbDeltaStore(getDatabase());
}
return mongoDbDeltaStore;
}
}