org.apache.flink.streaming.runtime.operators.windowing

Class WindowOperator.Context

java.lang.Object

org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.Context

All Implemented Interfaces:

Trigger.TriggerContext

Enclosing class:

WindowOperator<K,IN,OUT,W extends Window>

protected class WindowOperator.Context
extends Object
implements Trigger.TriggerContext

The Context is responsible for keeping track of the state of one pane.

A pane is the bucket of elements that have the same key (assigned by the KeySelector) and same Window. An element can be in multiple panes of it was assigned to multiple windows by the WindowAssigner. These panes all have their own instance of the Trigger.

Field Summary

Fields

Modifier and Type	Field and Description
protected K	key
protected long	processingTimeTimer
protected HashMap<String,Serializable>	state
protected long	watermarkTimer
protected W	window
protected WindowBuffer<IN>	windowBuffer

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	WindowOperator.Context(DataInputView in, ClassLoader userClassloader) Constructs a new Context by reading from a DataInputView that contains a serialized context that we wrote in writeToState(StateBackend.CheckpointStateOutputView)
	WindowOperator.Context(K key, W window, WindowBuffer<IN> windowBuffer)

Method Summary

Methods

Modifier and Type	Method and Description
<S extends Serializable> OperatorState<S>	getKeyValueState(String name, S defaultState) Retrieves an OperatorState object that can be used to interact with fault-tolerant state that is scoped to the window and key of the current trigger invocation.
Trigger.TriggerResult	onElement(StreamRecord<IN> element)
Trigger.TriggerResult	onEventTime(long time)
Trigger.TriggerResult	onProcessingTime(long time)
void	registerEventTimeTimer(long time) Register an event-time callback.
void	registerProcessingTimeTimer(long time) Register a system time callback.
protected void	writeToState(StateBackend.CheckpointStateOutputView out) Writes the Context to the given state checkpoint output.

Methods inherited from class java.lang.Object

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

Field Detail

key

protected K key

window

protected W extends Window window

windowBuffer

protected WindowBuffer<IN> windowBuffer

state

protected HashMap<String,Serializable> state

watermarkTimer

protected long watermarkTimer

processingTimeTimer

protected long processingTimeTimer

Constructor Detail

WindowOperator.Context

public WindowOperator.Context(K key,
                      W window,
                      WindowBuffer<IN> windowBuffer)

WindowOperator.Context

protected WindowOperator.Context(DataInputView in,
                      ClassLoader userClassloader)
                          throws Exception

Constructs a new Context by reading from a DataInputView that contains a serialized context that we wrote in writeToState(StateBackend.CheckpointStateOutputView)

Throws:

Exception

Method Detail

writeToState

protected void writeToState(StateBackend.CheckpointStateOutputView out)
                     throws IOException

Writes the Context to the given state checkpoint output.

Throws:

IOException

getKeyValueState

public <S extends Serializable> OperatorState<S> getKeyValueState(String name,
                                                         S defaultState)

Description copied from interface: Trigger.TriggerContext

Retrieves an OperatorState object that can be used to interact with fault-tolerant state that is scoped to the window and key of the current trigger invocation.

Specified by:

getKeyValueState in interface Trigger.TriggerContext

Parameters:

name - A unique key for the state.

defaultState - The default value of the state.

registerProcessingTimeTimer

public void registerProcessingTimeTimer(long time)

Description copied from interface: Trigger.TriggerContext

Register a system time callback. When the current system time passes the specified time Trigger.onProcessingTime(long, Window, TriggerContext) is called with the time specified here.

Specified by:

registerProcessingTimeTimer in interface Trigger.TriggerContext

Parameters:

time - The time at which to invoke Trigger.onProcessingTime(long, Window, TriggerContext)

registerEventTimeTimer

public void registerEventTimeTimer(long time)

Description copied from interface: Trigger.TriggerContext

Register an event-time callback. When the current watermark passes the specified time Trigger.onEventTime(long, Window, TriggerContext) is called with the time specified here.

Specified by:

registerEventTimeTimer in interface Trigger.TriggerContext

Parameters:

time - The watermark at which to invoke Trigger.onEventTime(long, Window, TriggerContext)

See Also:

Watermark

onElement

public Trigger.TriggerResult onElement(StreamRecord<IN> element)
                                throws Exception

Throws:

Exception

onProcessingTime

public Trigger.TriggerResult onProcessingTime(long time)
                                       throws Exception

Throws:

Exception

onEventTime

public Trigger.TriggerResult onEventTime(long time)
                                  throws Exception

Throws:

Exception