org.apache.sling.discovery

Interface ClusterView

public interface ClusterView

A ClusterView represents the instances of a cluster that are up and running and that all can see each other at a certain point in time.

A ClusterView can also consist of just one single instance.

Method Summary

Modifier and Type	Method and Description
String	getId() Returns an id of this cluster view
List<InstanceDescription>	getInstances() Provides the list of InstanceDescriptions with a stable ordering.
InstanceDescription	getLeader() Provides the InstanceDescription belonging to the leader instance.

Method Detail

getId

String getId()

Returns an id of this cluster view

Returns:

an id of this cluster view

getInstances

List<InstanceDescription> getInstances()

Provides the list of InstanceDescriptions with a stable ordering.

Stable ordering implies that unless an instance leaves the cluster (due to shutdown/crash/network problems) the instance keeps the relative position in the list.

Returns:

the list of InstanceDescriptions (with a stable ordering)

getLeader

InstanceDescription getLeader()

Provides the InstanceDescription belonging to the leader instance.

Every ClusterView is guaranteed to have one and only one leader.

The leader is stable: once a leader is elected it stays leader unless it leaves the cluster (due to shutdown/crash/network problems)

Returns:

the InstanceDescription belonging to the leader instance