com.atlassian.jira.cluster.heartbeat

Interface ClusterNodeHeartbeatService

All Known Implementing Classes:

AbstractClusterNodeHeartbeatService, NullClusterNodeHeartbeatService, StartableClusterNodeHeartbeatService

public interface ClusterNodeHeartbeatService

Provides a heartbeat for nodes of a cluster and utility methods for finding out about the "liveness" of other nodes.

Method Summary

Modifier and Type	Method and Description
Collection<String>	findLiveNodes() Returns all nodes that have sent a heartbeat within the default threshold time.
Collection<String>	findLiveNodes(long threshold) Returns all nodes that have sent a heartbeat within the given threshold.
Long	getLastHeartbeatTime(String nodeId) Returns the last time a heartbeat was sent by the given node.
String	getNodeId() Returns the node ID for this node.
boolean	isNodeLive(String nodeId) Checks whether the given cluster node is considered "live".

Method Detail

getNodeId

@Nonnull
String getNodeId()

Returns the node ID for this node.

Returns:

the node ID for this node.

isNodeLive

boolean isNodeLive(@Nonnull
                   String nodeId)

Checks whether the given cluster node is considered "live".

Each live node will be writing a heartbeat on a set schedule (eg once a minute). A node is considered live if it has written a heartbeat within a reasonable tolerance level (eg 5 minutes).

The tolerance level needs to be large enough to avoid certain expected slow-downs in the system including GC pauses, or just general slowness in the JVM / scheduler / network / database of the remote node.

Parameters:

nodeId - the cluster node to check

Returns:

true iff the given cluster node is still "live".

getLastHeartbeatTime

@Nullable
Long getLastHeartbeatTime(@Nonnull
                                    String nodeId)

Returns the last time a heartbeat was sent by the given node.

A null value indicates no heartbeats have ever been sent by the given node.

Parameters:

nodeId - the node

Returns:

the last time a heartbeat was sent by the given node.

findLiveNodes

@Nonnull
Collection<String> findLiveNodes()

Returns all nodes that have sent a heartbeat within the default threshold time.

Returns:

all nodes that have sent a heartbeat within the default threshold time.

See Also:

findLiveNodes(long)

findLiveNodes

@Nonnull
Collection<String> findLiveNodes(long threshold)

Returns all nodes that have sent a heartbeat within the given threshold.

Parameters:

threshold - the threshold in milliseconds

Returns:

all nodes that have sent a heartbeat within the given threshold.

See Also:

findLiveNodes()