ai.eloquent.raft

Class EloquentRaftNode

java.lang.Object

ai.eloquent.raft.EloquentRaftNode

All Implemented Interfaces:

java.lang.AutoCloseable

public class EloquentRaftNode
extends java.lang.Object
implements java.lang.AutoCloseable

A node in the Raft cluster. This is as lightweight a class as possible, marrying a RaftAlgorithm (purely functional with no actual transport logic) with an RaftTransport (pure transport logic) to produce a functioning node in the cluster.

Field Summary

Fields

Modifier and Type	Field and Description
RaftAlgorithm	algorithm The Raft algorithm.
RaftLifecycle	lifecycle The RaftLifecycle object that this Raft node is tied to.
RaftTransport	transport The Raft transport logic.

Constructor Summary

Constructors

Constructor and Description
EloquentRaftNode(RaftAlgorithm algorithm, RaftTransport transport, RaftLifecycle lifecycle) The straightforward constructor.

Method Summary

Modifier and Type	Method and Description
protected void	addErrorListener(RaftErrorListener errorListener) Keeps track of an additional RaftErrorListener in this class
boolean	bootstrap(boolean force) Bootstrap this node of the cluster.
protected void	clearErrorListeners() Clears all the RaftErrorListeners attached to this class.
void	close()
void	close(boolean allowClusterDeath) This does an orderly shutdown of this member of the Raft cluster, stopping its heartbeats and removing it from the cluster.
java.util.List<java.lang.String>	errors() Return any errors Raft has encountered.
boolean	isAlive() Returns true if we're currently alive, false if we've closed.
void	registerFailsafe(RaftFailsafe failsafe) Register a new failsafe to run occasionally on this node.
void	registerShutdownHook(java.lang.Runnable shutdownHook) This adds a hook to run before we shutdown this RaftNode.
protected void	removeErrorListener(RaftErrorListener errorListener) Stop listening from a specific RaftErrorListener
void	start() This begins the process of discovering and joining the Raft cluster as a member.
java.util.concurrent.CompletableFuture<java.lang.Boolean>	submitTransition(byte[] transition) Submit a transition to Raft.

Methods inherited from class java.lang.Object

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

Field Detail

algorithm

public final RaftAlgorithm algorithm

The Raft algorithm.

transport

public final RaftTransport transport

The Raft transport logic.

lifecycle

public final RaftLifecycle lifecycle

The RaftLifecycle object that this Raft node is tied to.

Constructor Detail

EloquentRaftNode

public EloquentRaftNode(RaftAlgorithm algorithm,
                        RaftTransport transport,
                        RaftLifecycle lifecycle)

The straightforward constructor.

Method Detail

addErrorListener

protected void addErrorListener(RaftErrorListener errorListener)

Keeps track of an additional RaftErrorListener in this class

Parameters:

errorListener -

removeErrorListener

protected void removeErrorListener(RaftErrorListener errorListener)

Stop listening from a specific RaftErrorListener

Parameters:

errorListener - The error listener to be removed

clearErrorListeners

protected void clearErrorListeners()

Clears all the RaftErrorListeners attached to this class.

registerShutdownHook

public void registerShutdownHook(java.lang.Runnable shutdownHook)

This adds a hook to run before we shutdown this RaftNode. The hook will run on the thread that calls close() on this EloquentRaftNode (generally the shutdown hook in RaftLifecycle, from RaftLifecycle.shutdown()).

Parameters:

shutdownHook - The hook to run on shutdown

start

public void start()

This begins the process of discovering and joining the Raft cluster as a member.

bootstrap

public boolean bootstrap(boolean force)

Bootstrap this node of the cluster. This will put it into a state where it can become a candidate and start elections.

Returns:

True if we could bootstrap the node.

submitTransition

public java.util.concurrent.CompletableFuture<java.lang.Boolean> submitTransition(byte[] transition)

Submit a transition to Raft.

Parameters:

transition - The transition we are submitting.

Returns:

A future for the transition, marking whether it completed successfully.

errors

public java.util.List<java.lang.String> errors()

Return any errors Raft has encountered.

isAlive

public boolean isAlive()

Returns true if we're currently alive, false if we've closed.

close

public void close(boolean allowClusterDeath)

This does an orderly shutdown of this member of the Raft cluster, stopping its heartbeats and removing it from the cluster. If blocking is true, this will wait until the cluster has at least one other member to carry on the state before shutting down.

WARNING: once closed, this cannot be reopened

Parameters:

allowClusterDeath - If true, allow the cluster to lose state and completely shut down. Otherwise, we wait for another live node to show up before shutting down (the default).

close

public void close()

Specified by:

close in interface java.lang.AutoCloseable

See Also:

close(boolean)

registerFailsafe

public void registerFailsafe(RaftFailsafe failsafe)

Register a new failsafe to run occasionally on this node.

Parameters:

failsafe - the one to register