org.axonframework.eventhandling

Interface EventTrackerStatus

public interface EventTrackerStatus

Interface describing the status of a Segment of a TrackingProcessor.

Method Summary

Modifier and Type	Method and Description
OptionalLong	getCurrentPosition() Return the estimated relative current token position this Segment represents.
Throwable	getError() Returns the exception that caused processing to fail, if present.
OptionalLong	getResetPosition() Return the relative position at which a reset was triggered for this Segment.
Segment	getSegment() The segment for which this status is valid.
TrackingToken	getTrackingToken() The tracking token of the last event that has been seen by this Segment.
boolean	isCaughtUp() Whether the Segment of this status has caught up with the head of the event stream.
boolean	isErrorState() Indicates whether this status represents an error.
boolean	isMerging() Indicates whether this Segment is still merging two (or more) Segments.
boolean	isReplaying() Indicates whether this Segment is still replaying previously processed Events.
OptionalLong	mergeCompletedPosition() Return the estimated relative token position this Segment will have after a merge operation is complete.

Method Detail

getSegment

Segment getSegment()

The segment for which this status is valid.

Returns:

segment for which this status is valid

isCaughtUp

boolean isCaughtUp()

Whether the Segment of this status has caught up with the head of the event stream. Note that this is no guarantee that this segment is still processing at (or near) real-time events. It merely indicates that this segment has been at the head of the stream since it started processing. It may have fallen back since then.

Returns:

whether the Segment of this status has caught up with the head of the event stream

isReplaying

boolean isReplaying()

Indicates whether this Segment is still replaying previously processed Events.

Note that this method will only recognize a replay if the tokens have been reset using TrackingEventProcessor.resetTokens(). Removing tokens directly from the underlying TokenStore will not be recognized as a replay.

Returns:

true if this segment is replaying historic events after a reset, otherwise false

isMerging

boolean isMerging()

Indicates whether this Segment is still merging two (or more) Segments. The merging process will be done once all Segments have reached the same position.

Returns:

true if this segment is merging Segments, otherwise false

mergeCompletedPosition

OptionalLong mergeCompletedPosition()

Return the estimated relative token position this Segment will have after a merge operation is complete. Will return a non-empty result as long as isMerging() } returns true. In case no estimation can be given or no merge in progress, an OptionalLong.empty() will be returned.

Returns:

return the estimated relative position this Segment will reach after a merge operation is complete.

getTrackingToken

TrackingToken getTrackingToken()

The tracking token of the last event that has been seen by this Segment.

The returned tracking token represents the position of this segment in the event stream. In case of a recent merge of segments, the token represents the lowest position of the two merged segments.

Returns:

tracking token of the last event that has been seen by this Segment

isErrorState

boolean isErrorState()

Indicates whether this status represents an error. When this method return true, the getError() will return the exception that caused the failure.

Returns:

true if an error was reported, otherwise false

getError

Throwable getError()

Returns the exception that caused processing to fail, if present. If the segment is being processed normally, this method returns null.

Returns:

the exception that caused processing to fail, or null when processing normally

getCurrentPosition

OptionalLong getCurrentPosition()

Return the estimated relative current token position this Segment represents. In case of replay is active, return the estimated relative position reached by merge operation. In case of merge is active, return the estimated relative position reached by merge operation. In case no estimation can be given, or no replay or merge in progress, an OptionalLong.empty() will be returned.

Returns:

return the estimated relative current token position this Segment represents

getResetPosition

OptionalLong getResetPosition()

Return the relative position at which a reset was triggered for this Segment. In case a replay finished or no replay is active, an OptionalLong.empty() will be returned.

Returns:

the relative position at which a reset was triggered for this Segment