com.mongodb
Class Mongo

java.lang.Object
  com.mongodb.Mongo

public class Mongo
extends Object

A database connection with internal pooling. For most application, you should have 1 Mongo instance for the entire JVM. The following are equivalent, and all connect to the local database running on the default port:

 Mongo mongo1 = new Mongo( "127.0.0.1" );
 Mongo mongo2 = new Mongo( "127.0.0.1", 27017 );
 Mongo mongo3 = new Mongo( new DBAddress( "127.0.0.1", 27017, "test" ) );
 Mongo mongo4 = new Mongo( new ServerAddress( "127.0.0.1") );
 

Mongo instances have connection pooling built in - see the requestStart and requestDone methods for more information. http://www.mongodb.org/display/DOCS/Java+Driver+Concurrency

Connecting to a Replica Pair

You can connect to a replica pair using the Java driver by passing two DBAddresses to the Mongo constructor. For example:

 DBAddress left = new DBAddress("localhost:27017/test");
 DBAddress right = new DBAddress("localhost:27018/test");

 Mongo mongo = new Mongo(left, right);
 

If the master of a replica pair goes down, there will be a brief lag before the slave becomes master. Thus, your application should be prepared to catch the exceptions that might be thrown in such a case: IllegalArgumentException, MongoException, and MongoException.Network (depending on when the connection drops).

Once the slave becomes master, the driver will begin using that connection as the master connection and the exceptions will stop being thrown.

Connecting to a Replica Set

You can connect to a replica set using the Java driver by passing several a list if ServerAddress to the Mongo constructor. For example:

 List addrs = new ArrayList();
 addrs.add( new ServerAddress( "localhost" , 27017 ) );
 addrs.add( new ServerAddress( "localhost" , 27018 ) );
 addrs.add( new ServerAddress( "localhost" , 27019 ) );

 Mongo mongo = new Mongo( addrs );
 

By default, all read and write operations will be made on the master. But it's possible to read from the slave(s) by using slaveOk:

 mongo.slaveOk();
 

Nested Class Summary

static class

Mongo.Holder Mongo.Holder is if you want to have a static place to hold instances of Mongo security is not enforced at this level, so need to do on your side

Field Summary

static int	MAJOR_VERSION
static int	MINOR_VERSION

Constructor Summary

Mongo()

Mongo(List<ServerAddress> replicaSetSeeds)
Creates a Mongo connection.

Mongo(List<ServerAddress> replicaSetSeeds, MongoOptions options)
Creates a Mongo connection.

Mongo(MongoURI uri)
Creates a Mongo connection.

Mongo(ServerAddress addr)
Connects to a (single) mongodb node

Mongo(ServerAddress addr, MongoOptions options)
Connects to a (single) mongo node using a given ServerAddress

Mongo(ServerAddress left, ServerAddress right)
Creates a Mongo connection in paired mode.

Mongo(ServerAddress left, ServerAddress right, MongoOptions options)
Creates a Mongo connection in paired mode.

Mongo(String host)
Connects to a (single) mongodb node (default port)

Mongo(String host, int port)
Connects to a (single) mongodb node

Mongo(String host, MongoOptions options)
Connects to a (single) mongodb node (default port)

Method Summary

void	addOption(int option)
void	close() closes all open connections this Mongo cannot be re-used
static DB	connect(DBAddress addr)
String	debugString()
void	dropDatabase(String dbName) Drops the database if it exists.
ServerAddress	getAddress() Gets the address of this database.
List<ServerAddress>	getAllAddress()
String	getConnectPoint()
List<String>	getDatabaseNames()
DB	getDB(String dbname)
int	getOptions()
String	getVersion()
WriteConcern	getWriteConcern() Get the write concern for this database.
void	resetOptions()
void	setOptions(int options)
void	setWriteConcern(WriteConcern concern) Set the write concern for this database.
void	slaveOk() makes this query ok to run on a slave node

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAJOR_VERSION

public static final int MAJOR_VERSION

See Also:

Constant Field Values

MINOR_VERSION

public static final int MINOR_VERSION

See Also:

Constant Field Values

Constructor Detail

Mongo

public Mongo()
      throws UnknownHostException,
             MongoException

Throws:

UnknownHostException

MongoException

Mongo

public Mongo(String host)
      throws UnknownHostException,
             MongoException

Connects to a (single) mongodb node (default port)

Parameters:

host - server to connect to

Throws:

UnknownHostException - if the database host cannot be resolved

MongoException

Mongo

public Mongo(String host,
             MongoOptions options)
      throws UnknownHostException,
             MongoException

Connects to a (single) mongodb node (default port)

Parameters:

host - server to connect to

options - options to use

Throws:

UnknownHostException - if the database host cannot be resolved

MongoException

Mongo

public Mongo(String host,
             int port)
      throws UnknownHostException,
             MongoException

Connects to a (single) mongodb node

Parameters:

host - the database's host address

port - the port on which the database is running

Throws:

UnknownHostException - if the database host cannot be resolved

MongoException

Mongo

public Mongo(ServerAddress addr)
      throws MongoException

Connects to a (single) mongodb node

Parameters:

addr - the database address

Throws:

MongoException

See Also:

ServerAddress

Mongo

public Mongo(ServerAddress addr,
             MongoOptions options)
      throws MongoException

Connects to a (single) mongo node using a given ServerAddress

Parameters:

addr - the database address

Throws:

MongoException

See Also:

ServerAddress

Mongo

public Mongo(ServerAddress left,
             ServerAddress right)
      throws MongoException

Creates a Mongo connection in paired mode.
This will also work for a replica set and will find all members (the master will be used by default).

Parameters:

left - left side of the pair

right - right side of the pair

Throws:

MongoException

See Also:

ServerAddress

Mongo

public Mongo(ServerAddress left,
             ServerAddress right,
             MongoOptions options)
      throws MongoException

Creates a Mongo connection in paired mode.
This will also work for a replica set and will find all members (the master will be used by default).

Parameters:

left - left side of the pair

right - right side of the pair

Throws:

MongoException

See Also:

ServerAddress

Mongo

public Mongo(List<ServerAddress> replicaSetSeeds)
      throws MongoException

Creates a Mongo connection.
This will work for a replica set, or pair, and will find all members (the master will be used by default).

Parameters:

replicaSetSeeds - Put as many servers as you can in the list and the system will figure out the rest.

Throws:

MongoException

See Also:

ServerAddress

Mongo

public Mongo(List<ServerAddress> replicaSetSeeds,
             MongoOptions options)
      throws MongoException

Creates a Mongo connection.
This will work for a replica set, or pair, and will find all members (the master will be used by default).

Parameters:

replicaSetSeeds - put as many servers as you can in the list. the system will figure the rest out

Throws:

MongoException

See Also:

ServerAddress

Mongo

public Mongo(MongoURI uri)
      throws MongoException,
             UnknownHostException

Creates a Mongo connection. If only one address is used it will only connect to that node, otherwise it will discover all nodes.

Throws:

MongoException

UnknownHostException

See Also:

examples:

mongodb://localhost

mongodb://fred:foobar@localhost/

MongoDB Doc Links

• connections

Method Detail

connect

public static DB connect(DBAddress addr)

getDB

public DB getDB(String dbname)

getDatabaseNames

public List<String> getDatabaseNames()
                              throws MongoException

Throws:

MongoException

dropDatabase

public void dropDatabase(String dbName)
                  throws MongoException

Drops the database if it exists.

Parameters:

dbName - name of database to drop

Throws:

MongoException

getVersion

public String getVersion()

debugString

public String debugString()

getConnectPoint

public String getConnectPoint()

getAddress

public ServerAddress getAddress()

Gets the address of this database.

Returns:

the address

getAllAddress

public List<ServerAddress> getAllAddress()

close

public void close()

closes all open connections this Mongo cannot be re-used

setWriteConcern

public void setWriteConcern(WriteConcern concern)

Set the write concern for this database. Will be used for writes to any collection in this database. See the documentation for WriteConcern for more information.

Parameters:

concern - write concern to use

getWriteConcern

public WriteConcern getWriteConcern()

Get the write concern for this database.

slaveOk

public void slaveOk()

makes this query ok to run on a slave node

addOption

public void addOption(int option)

setOptions

public void setOptions(int options)

resetOptions

public void resetOptions()

getOptions

public int getOptions()