com.mongodb
Class WriteConcern

java.lang.Object
  com.mongodb.WriteConcern

public class WriteConcern
extends Object

WriteConcern control the write behavior for with various options, as well as exception raising on error conditions.

w

• -1 = don't even report network errors
• 0 = default, don't call getLastError by default
• 1 = basic, call getLastError, but don't wait for slaves
• 2+= wait for slaves

wtimeout how long to wait for slaves before failing

• 0 = indefinite
• > 0 = ms to wait

fsync force fsync to disk

MongoDB Doc Links

• databases

Field Summary

static WriteConcern	FSYNC_SAFE Exceptions are raised for network issues, and server errors and the write operation waits for the server to flush the data to disk
static WriteConcern	NONE No exceptions are raised, even for network issues
static WriteConcern	NORMAL Exceptions are raised for network issues, but not server errors
static WriteConcern	REPLICAS_SAFE Exceptions are raised for network issues, and server errors; waits for at least 2 servers for the write operation
static WriteConcern	SAFE Exceptions are raised for network issues, and server errors; waits on a server for the write operation

Constructor Summary

WriteConcern()

WriteConcern(boolean fsync)

WriteConcern(int w)
Specifies the number of servers to wait for on the write operation, and exception raising behavior

WriteConcern(int w, int wtimeout)
Specifies the number of servers to wait for on the write operation, and the amount of time (ms) to wait.

WriteConcern(int w, int wtimeout, boolean fsync)
Specifies the number of servers to wait for on the write operation, and the amount of time (ms) to wait.

Method Summary

boolean	callGetLastError()
boolean	fsync()
BasicDBObject	getCommand()
int	getW()
int	getWtimeout()
boolean	raiseNetworkErrors()
String	toString()
static WriteConcern	valueOf(String name) Get the WriteConcern constants by name: NONE, NORMAL, SAFE, FSYNC_SAFE, REPLICA_SAFE.

Methods inherited from class java.lang.Object

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

Field Detail

NONE

public static final WriteConcern NONE

No exceptions are raised, even for network issues

NORMAL

public static final WriteConcern NORMAL

Exceptions are raised for network issues, but not server errors

SAFE

public static final WriteConcern SAFE

Exceptions are raised for network issues, and server errors; waits on a server for the write operation

FSYNC_SAFE

public static final WriteConcern FSYNC_SAFE

Exceptions are raised for network issues, and server errors and the write operation waits for the server to flush the data to disk

REPLICAS_SAFE

public static final WriteConcern REPLICAS_SAFE

Exceptions are raised for network issues, and server errors; waits for at least 2 servers for the write operation

Constructor Detail

WriteConcern

public WriteConcern()

WriteConcern

public WriteConcern(int w)

Specifies the number of servers to wait for on the write operation, and exception raising behavior

w represents # of servers:

• w=-1 None, no checking is done
• w=0 None, network socket errors raised
• w=1 Checks server for errors as well as network socket errors raised
• w>1 Checks servers (w) for errors as well as network socket errors raised

WriteConcern

public WriteConcern(int w,
                    int wtimeout)

Specifies the number of servers to wait for on the write operation, and the amount of time (ms) to wait.

Note: w should be > 1

WriteConcern

public WriteConcern(boolean fsync)

WriteConcern

public WriteConcern(int w,
                    int wtimeout,
                    boolean fsync)

Specifies the number of servers to wait for on the write operation, and the amount of time (ms) to wait.

Note: w should be > 1

Method Detail

valueOf

public static WriteConcern valueOf(String name)

Get the WriteConcern constants by name: NONE, NORMAL, SAFE, FSYNC_SAFE, REPLICA_SAFE. (matching is done case insensitively)

getCommand

public BasicDBObject getCommand()

getW

public int getW()

Returns:

the number of servers to write to

getWtimeout

public int getWtimeout()

Returns:

the write timeout (in milliseconds)

fsync

public boolean fsync()

Returns:

If files are sync'd to disk.

raiseNetworkErrors

public boolean raiseNetworkErrors()

callGetLastError

public boolean callGetLastError()

toString

public String toString()

Overrides:

toString in class Object