org.apache.flink.streaming.api.operators

Class AbstractUdfStreamOperator<OUT,F extends Function>

java.lang.Object

org.apache.flink.streaming.api.operators.AbstractStreamOperator<OUT>

org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator<OUT,F>

Type Parameters:

OUT - The output type of the operator

F - The type of the user function

All Implemented Interfaces:

Serializable, OutputTypeConfigurable<OUT>, StreamOperator<OUT>

Direct Known Subclasses:

AbstractAlignedProcessingTimeWindowOperator, CoStreamFlatMap, CoStreamMap, ExtractTimestampsOperator, NonKeyedWindowOperator, StreamFilter, StreamFlatMap, StreamGroupedFold, StreamGroupedReduce, StreamMap, StreamSink, StreamSource, WindowOperator

public abstract class AbstractUdfStreamOperator<OUT,F extends Function>
extends AbstractStreamOperator<OUT>
implements OutputTypeConfigurable<OUT>

This is used as the base class for operators that have a user-defined function. This class handles the opening and closing of the user-defined functions, as part of the operator life cycle.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected F	userFunction the user function

Fields inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

chainingStrategy, LOG, output

Constructor Summary

Constructors

Constructor and Description
AbstractUdfStreamOperator(F userFunction)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() This method is called after all records have been added to the operators via the methods OneInputStreamOperator.processElement(StreamRecord), or TwoInputStreamOperator.processElement1(StreamRecord) and TwoInputStreamOperator.processElement2(StreamRecord).
void	dispose() This method is called at the very end of the operator's life, both in the case of a successful completion of the operation, and in the case of a failure and canceling.
F	getUserFunction() Gets the user function executed in this operator.
Configuration	getUserFunctionParameters() Since the streaming API does not implement any parametrization of functions via a configuration, the config returned here is actually empty.
void	notifyOfCompletedCheckpoint(long checkpointId) Called when the checkpoint with the given ID is completed and acknowledged on the JobManager.
void	open() This method is called immediately before any elements are processed, it should contain the operator's initialization logic.
void	restoreState(StreamTaskState state) Restores the operator state, if this operator's execution is recovering from a checkpoint.
void	setOutputType(TypeInformation<OUT> outTypeInfo, ExecutionConfig executionConfig) Is called by the StreamGraph.addOperator(Integer, StreamOperator, TypeInformation, TypeInformation, String) method when the StreamGraph is generated.
void	setup(StreamTask<?,?> containingTask, StreamConfig config, Output<StreamRecord<OUT>> output) Initializes the operator.
StreamTaskState	snapshotOperatorState(long checkpointId, long timestamp) Called to draw a state snapshot from the operator.

Methods inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

createKeyValueState, createKeyValueState, disableInputCopy, getChainingStrategy, getContainingTask, getExecutionConfig, getOperatorConfig, getRuntimeContext, getStateBackend, getUserCodeClassloader, isInputCopyingDisabled, registerTimer, setChainingStrategy, setKeyContext, setKeyContextElement

Methods inherited from class java.lang.Object

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

Field Detail

userFunction

protected final F extends Function userFunction

the user function

Constructor Detail

AbstractUdfStreamOperator

public AbstractUdfStreamOperator(F userFunction)

Method Detail

getUserFunction

public F getUserFunction()

Gets the user function executed in this operator.

Returns:

The user function of this operator.

setup

public void setup(StreamTask<?,?> containingTask,
         StreamConfig config,
         Output<StreamRecord<OUT>> output)

Description copied from interface: StreamOperator

Initializes the operator. Sets access to the context and the output.

Specified by:

setup in interface StreamOperator<OUT>

Overrides:

setup in class AbstractStreamOperator<OUT>

open

public void open()
          throws Exception

Description copied from class: AbstractStreamOperator

This method is called immediately before any elements are processed, it should contain the operator's initialization logic.

The default implementation does nothing.

Specified by:

open in interface StreamOperator<OUT>

Overrides:

open in class AbstractStreamOperator<OUT>

Throws:

Exception - An exception in this method causes the operator to fail.

close

public void close()
           throws Exception

Description copied from class: AbstractStreamOperator

This method is called after all records have been added to the operators via the methods OneInputStreamOperator.processElement(StreamRecord), or TwoInputStreamOperator.processElement1(StreamRecord) and TwoInputStreamOperator.processElement2(StreamRecord).

The method is expected to flush all remaining buffered data. Exceptions during this flushing of buffered should be propagated, in order to cause the operation to be recognized asa failed, because the last data items are not processed properly.

Specified by:

close in interface StreamOperator<OUT>

Overrides:

close in class AbstractStreamOperator<OUT>

Throws:

Exception - An exception in this method causes the operator to fail.

dispose

public void dispose()

Description copied from class: AbstractStreamOperator

This method is called at the very end of the operator's life, both in the case of a successful completion of the operation, and in the case of a failure and canceling. This method is expected to make a thorough effort to release all resources that the operator has acquired.

Specified by:

dispose in interface StreamOperator<OUT>

Overrides:

dispose in class AbstractStreamOperator<OUT>

snapshotOperatorState

public StreamTaskState snapshotOperatorState(long checkpointId,
                                    long timestamp)
                                      throws Exception

Description copied from interface: StreamOperator

Called to draw a state snapshot from the operator. This method snapshots the operator state (if the operator is stateful) and the key/value state (if it is being used and has been initialized).

Specified by:

snapshotOperatorState in interface StreamOperator<OUT>

Overrides:

snapshotOperatorState in class AbstractStreamOperator<OUT>

Parameters:

checkpointId - The ID of the checkpoint.

timestamp - The timestamp of the checkpoint.

Returns:

The StreamTaskState object, possibly containing the snapshots for the operator and key/value state.

Throws:

Exception - Forwards exceptions that occur while drawing snapshots from the operator and the key/value state.

restoreState

public void restoreState(StreamTaskState state)
                  throws Exception

Description copied from interface: StreamOperator

Restores the operator state, if this operator's execution is recovering from a checkpoint. This method restores the operator state (if the operator is stateful) and the key/value state (if it had been used and was initialized when the snapshot ocurred).

This method is called after StreamOperator.setup(StreamTask, StreamConfig, Output) and before StreamOperator.open().

Specified by:

restoreState in interface StreamOperator<OUT>

Overrides:

restoreState in class AbstractStreamOperator<OUT>

Parameters:

state - The state of operator that was snapshotted as part of checkpoint from which the execution is restored.

Throws:

Exception - Exceptions during state restore should be forwarded, so that the system can properly react to failed state restore and fail the execution attempt.

notifyOfCompletedCheckpoint

public void notifyOfCompletedCheckpoint(long checkpointId)
                                 throws Exception

Description copied from interface: StreamOperator

Called when the checkpoint with the given ID is completed and acknowledged on the JobManager.

Specified by:

notifyOfCompletedCheckpoint in interface StreamOperator<OUT>

Overrides:

notifyOfCompletedCheckpoint in class AbstractStreamOperator<OUT>

Parameters:

checkpointId - The ID of the checkpoint that has been completed.

Throws:

Exception - Exceptions during checkpoint acknowledgement may be forwarded and will cause the program to fail and enter recovery.

setOutputType

public void setOutputType(TypeInformation<OUT> outTypeInfo,
                 ExecutionConfig executionConfig)

Description copied from interface: OutputTypeConfigurable

Is called by the StreamGraph.addOperator(Integer, StreamOperator, TypeInformation, TypeInformation, String) method when the StreamGraph is generated. The method is called with the output TypeInformation which is also used for the StreamTask output serializer.

Specified by:

setOutputType in interface OutputTypeConfigurable<OUT>

Parameters:

outTypeInfo - Output type information of the StreamTask

executionConfig - Execution configuration

getUserFunctionParameters

public Configuration getUserFunctionParameters()

Since the streaming API does not implement any parametrization of functions via a configuration, the config returned here is actually empty.

Returns:

The user function parameters (currently empty)