Class CsnGenerator

java.lang.Object

org.opends.server.replication.common.CsnGenerator

public final class CsnGenerator
extends Object

This class defines a structure that is used for storing the last Csns generated on this server or received from other servers and generating new Csns that are guaranteed to be larger than all the previously seen or generated CSNs.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	CsnGenerator.StreamSequenceNumberGenerator	Generate a sequence number for a stream.

Method Summary

Modifier and Type	Method	Description
void	adjust(Csn csn)	Adjust the lastTime of this CsnGenerator with a Csn that we have received from another server.
void	adjust(ServerState state)	Adjust utility method that takes ServerState as a parameter.
Csn	generateCsn()	Returns the generated Csn.
Csn	generateCsnV3(long streamTimeStamp, long curTime, CsnGenerator.StreamSequenceNumberGenerator streamSeqNumGen)	Generate a new Csn using the V3 format.
static boolean	isSequenceBroken(Csn csn1, Csn csn2)	Checks whether the sequence is broken between two Csns.
static CsnGenerator	newCsnGenerator(ReplicaId replicaId, long timestamp)	Create a new CsnGenerator.
static CsnGenerator	newCsnGenerator(ReplicaId replicaId, LongSupplier timeSupplier)	Create a new CsnGenerator.
static CsnGenerator.StreamSequenceNumberGenerator	newStreamSequenceNumberGenerator()	Returns a new CsnGenerator.StreamSequenceNumberGenerator.
static long	nextStreamSeqNum(long streamSeqNum)	Returns the next stream sequence number.

Methods inherited from class Object

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

Method Details

newCsnGenerator

public static CsnGenerator newCsnGenerator(ReplicaId replicaId,
 long timestamp)

Create a new CsnGenerator.

Parameters:

replicaId - id to use when creating Csns.

timestamp - time to start with.

Returns:

the new CsnGenerator

newCsnGenerator

public static CsnGenerator newCsnGenerator(ReplicaId replicaId,
 LongSupplier timeSupplier)

Create a new CsnGenerator.

Parameters:

replicaId - the replicaId to use when creating Csns

timeSupplier - the timestamp supplier

Returns:

the new CsnGenerator

newStreamSequenceNumberGenerator

public static CsnGenerator.StreamSequenceNumberGenerator newStreamSequenceNumberGenerator()

Returns a new CsnGenerator.StreamSequenceNumberGenerator.

Returns:

a new CsnGenerator.StreamSequenceNumberGenerator

generateCsn

public Csn generateCsn()

Returns the generated Csn.

Returns:

the generated Csn

generateCsnV3

public Csn generateCsnV3(long streamTimeStamp,
 long curTime,
 CsnGenerator.StreamSequenceNumberGenerator streamSeqNumGen)

Generate a new Csn using the V3 format.

Parameters:

streamTimeStamp - the streamId to use when creating the Csn

curTime - the current time

streamSeqNumGen - the stream sequence number generator

Returns:

the generated Csn

nextStreamSeqNum

public static long nextStreamSeqNum(long streamSeqNum)

Returns the next stream sequence number.

Parameters:

streamSeqNum - the current stream sequence number

Returns:

the next stream sequence number

isSequenceBroken

public static boolean isSequenceBroken(Csn csn1,
 Csn csn2)

Checks whether the sequence is broken between two Csns.

Parameters:

csn1 - the first Csn

csn2 - the second Csn

Returns:

if the two csns are in sequence

adjust

public void adjust(ServerState state)

Adjust utility method that takes ServerState as a parameter.

Parameters:

state - the ServerState to adjust with

adjust

public void adjust(Csn csn)

Adjust the lastTime of this CsnGenerator with a Csn that we have received from another server.

This is necessary because we need that the Csn generated after processing an update received from other hosts to be as close as possible to the received Csn in order to have a global ordering that is close to wall-clock time.

Parameters:

csn - the Csn to adjust with