Package org.apache.ignite.events

Interface Event

All Superinterfaces:

Comparable<Event>, Serializable

All Known Implementing Classes:

BaselineChangedEvent, BaselineConfigurationChangedEvent, CacheConsistencyViolationEvent, CacheEvent, CacheObjectTransformedEvent, CacheQueryExecutedEvent, CacheQueryReadEvent, CacheRebalancingEvent, CheckpointEvent, ClusterActivationEvent, ClusterStateChangeEvent, ClusterStateChangeStartedEvent, ClusterTagUpdatedEvent, DeploymentEvent, DiscoveryEvent, EventAdapter, JobEvent, NodeValidationFailedEvent, PageReplacementStartedEvent, SnapshotEvent, SqlQueryExecutionEvent, TaskEvent, TransactionStateChangedEvent, WalSegmentArchivedEvent, WalSegmentCompactedEvent

public interface Event
extends Comparable<Event>, Serializable

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...) - 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).

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 either 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.

Internal and Hidden Events

Also note that some events are considered to be internally used or hidden.

Internally used events are always "recordable" for notification purposes (regardless of whether they were enabled or disabled). But won't be sent down to SPI level if user specifically excluded them.

All discovery events are internal:

• EventType.EVT_NODE_FAILED
• EventType.EVT_NODE_LEFT
• EventType.EVT_NODE_JOINED
• EventType.EVT_NODE_METRICS_UPDATED
• EventType.EVT_NODE_SEGMENTED

Hidden events are NEVER sent to SPI level. They serve purpose of local notification for the local node.

Hidden events:

• EventType.EVT_NODE_METRICS_UPDATED

See Also:

JobEvent, CacheEvent, CacheRebalancingEvent, CheckpointEvent, DeploymentEvent, DiscoveryEvent, TaskEvent, IgniteEvents.waitForLocal(org.apache.ignite.lang.IgnitePredicate, int...)

Method Summary

Modifier and Type	Method	Description
IgniteUuid	id()	Gets globally unique ID of this event.
long	localOrder()	Gets locally unique ID that is atomically incremented for each event.
@Nullable String	message()	Gets optional message for this event.
String	name()	Gets name of this event.
ClusterNode	node()	Node where event occurred and was recorded
String	shortDisplay()	Gets a shortened version of toString() result.
long	timestamp()	Gets event timestamp.
int	type()	Gets type of this event.

Methods inherited from interface java.lang.Comparable

compareTo

Method Detail

id

IgniteUuid id()

Gets globally unique ID of this event.

Returns:

Globally unique ID of this event.

See Also:

localOrder()

localOrder

long localOrder()

Gets locally unique ID that is atomically incremented for each event. Unlike global id() this local ID can be used for ordering events on this node.

Note that for performance considerations Ignite doesn't order events globally.

Returns:

Locally unique ID that is atomically incremented for each new event.

See Also:

id()

node

ClusterNode node()

Node where event occurred and was recorded

Returns:

node where event occurred and was recorded.

message

@Nullable
@Nullable String message()

Gets optional message for this event.

Returns:

Optional (can be null) message for this event.

type

int type()

Gets type of this event. All system event types are defined in EventType.

NOTE: all types in range from 1 to 1000 are reserved for internal Ignite events and should not be used by user-defined events.

Returns:

Event's type.

See Also:

EventType

name

String name()

Gets name of this event. All events are defined in EventType class.

Returns:

Name of this event.

timestamp

long timestamp()

Gets event timestamp. Timestamp is local to the node on which this event was produced. Note that more than one event can be generated with the same timestamp. For ordering purposes use localOrder() instead.

Returns:

Event timestamp.

shortDisplay

String shortDisplay()

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

Returns:

Shortened version of toString() result.