com.mongodb
Class WriteConcern

java.lang.Object
  com.mongodb.WriteConcern

Direct Known Subclasses:

WriteConcern.Majority

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

Nested Class Summary

static class

WriteConcern.Majority

Field Summary

static WriteConcern	FSYNC_SAFE Exceptions are raised for network issues, and server errors; the write operation waits for the server to flush the data to disk
static WriteConcern	JOURNAL_SAFE Exceptions are raised for network issues, and server errors; the write operation waits for the server to group commit to the journal file on disk
static WriteConcern	MAJORITY Exceptions are raised for network issues, and server errors; waits on a majority of servers for the write operation
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()
Default constructor keeping all options as default

WriteConcern(boolean fsync)
Calls WriteConcern(int, int, boolean) with w=1 and wtimeout=0

WriteConcern(int w)
Calls WriteConcern(int, int, boolean) with wtimeout=0 and fsync=false

WriteConcern(int w, int wtimeout)
Calls WriteConcern(int, int, boolean) with fsync=false

WriteConcern(int w, int wtimeout, boolean fsync)
Creates a WriteConcern object.

WriteConcern(int w, int wtimeout, boolean fsync, boolean j)
Creates a WriteConcern object.

WriteConcern(String w)
Tag based Write Concern with wtimeout=0, fsync=false, and j=false

WriteConcern(String w, int wtimeout, boolean fsync, boolean j)
Creates a WriteConcern object.

Method Summary

boolean	callGetLastError() Returns whether "getlasterror" should be called (w > 0)
boolean	equals(Object o)
boolean	fsync() Gets the fsync flag (fsync to disk on the server)
BasicDBObject	getCommand() Gets the object representing the "getlasterror" command
boolean	getContinueOnErrorForInsert() Gets the "continue inserts on error" mode
boolean	getFsync() Gets the fsync flag (fsync to disk on the server)
boolean	getJ() Gets the j parameter (journal syncing)
int	getW() Gets the w parameter (the write strategy)
Object	getWObject() Gets the w value (the write strategy)
String	getWString() Gets the w parameter (the write strategy) in String format
int	getWtimeout() Gets the write timeout (in milliseconds)
static WriteConcern.Majority	majorityWriteConcern(int wtimeout, boolean fsync, boolean j) Create a Majority Write Concern that requires a majority of servers to acknowledge the write.
boolean	raiseNetworkErrors() Returns whether network error may be raised (w >= 0)
void	setContinueOnErrorForInsert(boolean continueOnErrorForInsert) Sets the "continue inserts on error" mode.
void	setFsync(boolean fsync) Sets the fsync flag (fsync to disk on the server)
void	setJ(boolean j) Sets the j parameter (journal syncing)
void	setW(int w) Sets the w value (the write strategy)
void	setWObject(Object w) Sets the w value (the write strategy)
void	setWtimeout(int wtimeout) Sets the write timeout (in milliseconds)
String	toString()
static WriteConcern	valueOf(String name) Gets the WriteConcern constants by name: NONE, NORMAL, SAFE, FSYNC_SAFE, REPLICA_SAFE.

Methods inherited from class java.lang.Object

clone, 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

MAJORITY

public static final WriteConcern MAJORITY

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

FSYNC_SAFE

public static final WriteConcern FSYNC_SAFE

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

JOURNAL_SAFE

public static final WriteConcern JOURNAL_SAFE

Exceptions are raised for network issues, and server errors; the write operation waits for the server to group commit to the journal file on 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()

Default constructor keeping all options as default

WriteConcern

public WriteConcern(int w)

Calls WriteConcern(int, int, boolean) with wtimeout=0 and fsync=false

Parameters:

w - number of writes

WriteConcern

public WriteConcern(String w)

Tag based Write Concern with wtimeout=0, fsync=false, and j=false

Parameters:

w - Write Concern tag

WriteConcern

public WriteConcern(int w,
                    int wtimeout)

Calls WriteConcern(int, int, boolean) with fsync=false

Parameters:

w - number of writes

wtimeout - timeout for write operation

WriteConcern

public WriteConcern(boolean fsync)

Calls WriteConcern(int, int, boolean) with w=1 and wtimeout=0

Parameters:

fsync - whether or not to fsync

WriteConcern

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

Creates a WriteConcern object.

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

w represents the number 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

Parameters:

w - number of writes

wtimeout - timeout for write operation

fsync - whether or not to fsync

WriteConcern

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

Creates a WriteConcern object.

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

w represents the number 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

Parameters:

w - number of writes

wtimeout - timeout for write operation

fsync - whether or not to fsync

j - whether writes should wait for a journaling group commit

WriteConcern

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

Creates a WriteConcern object.

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

w represents the number 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

Parameters:

w - number of writes

wtimeout - timeout for write operation

fsync - whether or not to fsync

j - whether writes should wait for a journaling group commit

Method Detail

getCommand

public BasicDBObject getCommand()

Gets the object representing the "getlasterror" command

Returns:

setWObject

public void setWObject(Object w)

Sets the w value (the write strategy)

Parameters:

wValue -

getWObject

public Object getWObject()

Gets the w value (the write strategy)

Returns:

setW

public void setW(int w)

Sets the w value (the write strategy)

Parameters:

w -

getW

public int getW()

Gets the w parameter (the write strategy)

Returns:

getWString

public String getWString()

Gets the w parameter (the write strategy) in String format

Returns:

setWtimeout

public void setWtimeout(int wtimeout)

Sets the write timeout (in milliseconds)

Parameters:

wtimeout -

getWtimeout

public int getWtimeout()

Gets the write timeout (in milliseconds)

Returns:

setFsync

public void setFsync(boolean fsync)

Sets the fsync flag (fsync to disk on the server)

Parameters:

fsync -

getFsync

public boolean getFsync()

Gets the fsync flag (fsync to disk on the server)

Returns:

fsync

public boolean fsync()

Gets the fsync flag (fsync to disk on the server)

Returns:

raiseNetworkErrors

public boolean raiseNetworkErrors()

Returns whether network error may be raised (w >= 0)

Returns:

callGetLastError

public boolean callGetLastError()

Returns whether "getlasterror" should be called (w > 0)

Returns:

valueOf

public static WriteConcern valueOf(String name)

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

Parameters:

name -

Returns:

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

setJ

public void setJ(boolean j)

Sets the j parameter (journal syncing)

Parameters:

j -

getJ

public boolean getJ()

Gets the j parameter (journal syncing)

Returns:

setContinueOnErrorForInsert

public void setContinueOnErrorForInsert(boolean continueOnErrorForInsert)

Sets the "continue inserts on error" mode. This only applies to server side errors. If there is a document which does not validate in the client, an exception will still be thrown in the client.

Parameters:

continueOnErrorForInsert -

getContinueOnErrorForInsert

public boolean getContinueOnErrorForInsert()

Gets the "continue inserts on error" mode

Returns:

majorityWriteConcern

public static WriteConcern.Majority majorityWriteConcern(int wtimeout,
                                                         boolean fsync,
                                                         boolean j)

Create a Majority Write Concern that requires a majority of servers to acknowledge the write.

Parameters:

wtimeout - timeout for write operation

fsync - whether or not to fsync

j - whether writes should wait for a journaling group commit