org.apache.ignite.events

Class DiscoveryEvent

java.lang.Object

org.apache.ignite.events.EventAdapter

org.apache.ignite.events.DiscoveryEvent

All Implemented Interfaces:

Serializable, Comparable<Event>, Event

public class DiscoveryEvent
extends EventAdapter

Grid discovery event.

Grid events are used for notification about what happens within the grid. Note that by design Ignite keeps all events generated on the local node locally and it provides APIs for performing a distributed queries across multiple nodes:

• IgniteEvents.remoteQuery(org.apache.ignite.lang.IgnitePredicate, long, int...) - asynchronously querying events occurred on the nodes specified, including remote nodes.
• IgniteEvents.localQuery(org.apache.ignite.lang.IgnitePredicate, int...) - querying only local events stored on this local node.
• IgniteEvents.localListen(org.apache.ignite.lang.IgnitePredicate, int...) - listening to local grid events (events from remote nodes not included).

User can also wait for events using method IgniteEvents.waitForLocal(org.apache.ignite.lang.IgnitePredicate, int...).

Events and Performance

Note that by default all events in Ignite are enabled and therefore generated and stored by whatever event storage SPI is configured. Ignite can and often does generate thousands events per seconds under the load and therefore it creates a significant additional load on the system. If these events are not needed by the application this load is unnecessary and leads to significant performance degradation.

It is highly recommended to enable only those events that your application logic requires by using IgniteConfiguration.getIncludeEventTypes() method in Ignite configuration. Note that certain events are required for Ignite's internal operations and such events will still be generated but not stored by event storage SPI if they are disabled in Ignite configuration.

See Also:

EventType.EVT_NODE_METRICS_UPDATED, EventType.EVT_NODE_FAILED, EventType.EVT_NODE_JOINED, EventType.EVT_NODE_LEFT, EventType.EVT_NODE_SEGMENTED, EventType.EVTS_DISCOVERY_ALL, EventType.EVTS_DISCOVERY, Serialized Form

Constructor Summary

Constructors

Constructor and Description
DiscoveryEvent() No-arg constructor.
DiscoveryEvent(ClusterNode node, String msg, int type, ClusterNode evtNode) Creates new discovery event with given parameters.

Method Summary

Modifier and Type	Method and Description
ClusterNode	eventNode() Gets node that caused this event to be generated.
void	eventNode(ClusterNode evtNode) Sets node this event is referring to.
String	shortDisplay() Gets a shortened version of toString() result.
Collection<ClusterNode>	topologyNodes() Gets topology nodes from topology snapshot.
void	topologySnapshot(long topVer, Collection<ClusterNode> topSnapshot) Sets the topology snapshot.
long	topologyVersion() Gets topology version if this event is raised on topology change and configured discovery SPI implementation supports topology versioning.
String	toString()

Methods inherited from class org.apache.ignite.events.EventAdapter

compareTo, equals, hashCode, id, localOrder, message, message, name, node, node, timestamp, type, type

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DiscoveryEvent

public DiscoveryEvent()

No-arg constructor.

DiscoveryEvent

public DiscoveryEvent(ClusterNode node,
                      String msg,
                      int type,
                      ClusterNode evtNode)

Creates new discovery event with given parameters.

Parameters:

node - Local node.

msg - Optional event message.

type - Event type.

evtNode - Node that caused this event to be generated.

Method Detail

shortDisplay

public String shortDisplay()

Gets a shortened version of toString() result. Suitable for humans to read.

Specified by:

shortDisplay in interface Event

Overrides:

shortDisplay in class EventAdapter

Returns:

Shortened version of toString() result.

eventNode

public void eventNode(ClusterNode evtNode)

Sets node this event is referring to.

Parameters:

evtNode - Event node.

eventNode

public ClusterNode eventNode()

Gets node that caused this event to be generated. It is potentially different from the node on which this event was recorded. For example, node A locally recorded the event that a remote node B joined the topology. In this case this method will return node B.

Returns:

Event node.

topologyVersion

public long topologyVersion()

Gets topology version if this event is raised on topology change and configured discovery SPI implementation supports topology versioning.

Returns:

Topology version or 0 if configured discovery SPI implementation does not support versioning.

topologyNodes

public Collection<ClusterNode> topologyNodes()

Gets topology nodes from topology snapshot. If SPI implementation does not support versioning, the best effort snapshot will be captured.

Returns:

Topology snapshot.

topologySnapshot

public void topologySnapshot(long topVer,
                             Collection<ClusterNode> topSnapshot)

Sets the topology snapshot.

Parameters:

topVer - Topology version.

topSnapshot - Topology snapshot.

toString

public String toString()

Overrides:

toString in class EventAdapter