org.reveno.atp.clustering.api

Interface Cluster

All Known Implementing Classes:

JGroupsCluster

public interface Cluster

In Reveno, Cluster is an interface which denotes the notion of group of Reveno hosts, which works according to Master-Slave principle. According to it, there is single Master host, which receives incoming Transaction Commands and some number of Slave ones, which receives Commands in failover mode from Master, means they produce no events and just keeps the same state as Master, so, in case of any Master failure, they can re-elect new leader, which will start from the same point the previous Master node had stopped. In Reveno clustering ecosystem, the whole failover engine is separeted into two big parts: - Coordination part - Failover part Cluster interface is the part of "Coordination part", which plays next roles: - Connect/Disconnect to other nodes - Keep track of current cluster members via ClusterView - Perform leadership election in case of any cluster membership changes - Prevent cluster from "split-brain" phenomen. - Provide internal system messaging between nodes.

Method Summary

Modifier and Type	Method and Description
void	connect() Connects to the current Reveno group of nodes.
void	disconnect() Marks itself as detached from the cluster, and frees all allocated resources and connections for it.
ClusterConnector	gateway() Provides gateway instance which provides with communication ability between nodes via sending Messages to each other.
boolean	isConnected() Checks whether current node is included in current group of hosts.
void	listenEvents(java.util.function.Consumer<ClusterEvent> consumer) Subscribes to the set of events, which can eventually be issued, reflecting some changes in membership, etc.
void	marshallWith(Marshaller marshaller) Sets the marshaller instance, which will be used to marshall/unmarshall all incoming/outgoing messages.
ClusterView	view() Returns the current Reveno Cluster View.

Method Detail

connect

void connect()

Connects to the current Reveno group of nodes. Depending on the concrete implementation, either physical connection is opened (TCP protocol for example), or not (UPD protocol for example). In any case, it allows to performs much of initialization things.

disconnect

void disconnect()

Marks itself as detached from the cluster, and frees all allocated resources and connections for it.

isConnected

boolean isConnected()

Checks whether current node is included in current group of hosts.

Returns:

gateway

ClusterConnector gateway()

Provides gateway instance which provides with communication ability between nodes via sending Messages to each other.

Returns:

marshallWith

void marshallWith(Marshaller marshaller)

Sets the marshaller instance, which will be used to marshall/unmarshall all incoming/outgoing messages. Surely, all nodes in cluster should use the same one.

Parameters:

marshaller -

listenEvents

void listenEvents(java.util.function.Consumer<ClusterEvent> consumer)

Subscribes to the set of events, which can eventually be issued, reflecting some changes in membership, etc.

Parameters:

consumer -

view

ClusterView view()

Returns the current Reveno Cluster View. It is represented by unique nubmer and the list of current active members which are in current group. If new node(s) comes in/out of the cluster, new View instance is registered among all rest active nodes, which in turn require new leadership election process to be started.

Returns: