org.eclipse.jgit.internal.ketch

Class Round

java.lang.Object

org.eclipse.jgit.internal.ketch.Round

Direct Known Subclasses:

ElectionRound, ProposalRound

abstract class Round
extends java.lang.Object

One round-trip to all replicas proposing a log entry.

In Raft a log entry represents a state transition at a specific index in the replicated log. The leader can only append log entries to the log.

In Ketch a log entry is recorded under the refs/txn namespace. This occurs when:

• a replica wants to establish itself as a new leader by proposing a new term (see ElectionRound)
• an established leader wants to gain consensus on new Proposals (see ProposalRound)

Field Summary

Fields

Modifier and Type	Field and Description
(package private) LogIndex	acceptedNewIndex
(package private) LogIndex	acceptedOldIndex
(package private) KetchLeader	leader
(package private) java.util.List<ReceiveCommand>	stageCommands

Constructor Summary

Constructors

Constructor and Description
Round(KetchLeader leader, LogIndex head)

Method Summary

Modifier and Type	Method and Description
(package private) KetchSystem	getSystem()
(package private) void	runAsync(AnyObjectId newId) Asynchronously distribute the round's new value for refs/txn/accepted to all replicas.
(package private) abstract void	start() Creates a commit for refs/txn/accepted and calls runAsync(AnyObjectId) to begin execution of the round across the system.
(package private) abstract void	success() Notify the round it was accepted by a majority of the system.

Methods inherited from class java.lang.Object

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

Field Detail

leader

final KetchLeader leader

acceptedOldIndex

final LogIndex acceptedOldIndex

acceptedNewIndex

LogIndex acceptedNewIndex

stageCommands

java.util.List<ReceiveCommand> stageCommands

Constructor Detail

Round

Round(KetchLeader leader,
      LogIndex head)

Method Detail

getSystem

KetchSystem getSystem()

start

abstract void start()
             throws java.io.IOException

Creates a commit for refs/txn/accepted and calls runAsync(AnyObjectId) to begin execution of the round across the system.

If references are being updated (such as in a ProposalRound) the RefTree may be modified.

Invoked without KetchLeader.lock to build objects.

Throws:

java.io.IOException - the round cannot build new objects within the leader's repository. The leader may be unable to execute.

runAsync

void runAsync(AnyObjectId newId)

Asynchronously distribute the round's new value for refs/txn/accepted to all replicas.

Invoked by start() after new commits have been created for the log. The method passes newId to KetchLeader to be distributed to all known replicas.

Parameters:

newId - new value for refs/txn/accepted.

success

abstract void success()

Notify the round it was accepted by a majority of the system.

Invoked by the leader with KetchLeader.lock held by the caller.