org.apache.spark.sql.streaming

Class StreamingQueryListener

Object

org.apache.spark.sql.streaming.StreamingQueryListener

public abstract class StreamingQueryListener
extends Object

Interface for listening to events related to StreamingQueries.

Since:

2.0.0

Note:

The methods are not thread-safe as they may be called from different threads.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	StreamingQueryListener.Event Base type of StreamingQueryListener events
static class	StreamingQueryListener.QueryProgressEvent Event representing any progress updates in a query.
static class	StreamingQueryListener.QueryStartedEvent Event representing the start of a query param: id A unique query id that persists across restarts.
static class	StreamingQueryListener.QueryTerminatedEvent Event representing that termination of a query.

Constructor Summary

Constructors

Constructor and Description
StreamingQueryListener()

Method Summary

Modifier and Type	Method and Description
abstract void	onQueryProgress(StreamingQueryListener.QueryProgressEvent event) Called when there is some status update (ingestion rate updated, etc.)
abstract void	onQueryStarted(StreamingQueryListener.QueryStartedEvent event) Called when a query is started.
abstract void	onQueryTerminated(StreamingQueryListener.QueryTerminatedEvent event) Called when a query is stopped, with or without error.

Methods inherited from class Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StreamingQueryListener

public StreamingQueryListener()

Method Detail

onQueryStarted

public abstract void onQueryStarted(StreamingQueryListener.QueryStartedEvent event)

Called when a query is started.

Parameters:

event - (undocumented)

Since:

2.0.0

Note:

This is called synchronously with DataStreamWriter.start(), that is, onQueryStart will be called on all listeners before DataStreamWriter.start() returns the corresponding StreamingQuery. Please don't block this method as it will block your query.

onQueryProgress

public abstract void onQueryProgress(StreamingQueryListener.QueryProgressEvent event)

Called when there is some status update (ingestion rate updated, etc.)

Parameters:

event - (undocumented)

Since:

2.0.0

Note:

This method is asynchronous. The status in StreamingQuery will always be latest no matter when this method is called. Therefore, the status of StreamingQuery may be changed before/when you process the event. E.g., you may find StreamingQuery is terminated when you are processing QueryProgressEvent.

onQueryTerminated

public abstract void onQueryTerminated(StreamingQueryListener.QueryTerminatedEvent event)

Called when a query is stopped, with or without error.

Parameters:

event - (undocumented)

Since:

2.0.0