org.apache.flink.streaming.api.functions.source

Class ContinuousFileReaderOperator<OUT,S extends Serializable>

java.lang.Object

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

org.apache.flink.streaming.api.functions.source.ContinuousFileReaderOperator<OUT,S>

All Implemented Interfaces:

Serializable, AsyncExceptionChecker, OneInputStreamOperator<org.apache.flink.core.fs.FileInputSplit,OUT>, OutputTypeConfigurable<OUT>, StreamOperator<OUT>

@Internal
public class ContinuousFileReaderOperator<OUT,S extends Serializable>
extends AbstractStreamOperator<OUT>
implements OneInputStreamOperator<org.apache.flink.core.fs.FileInputSplit,OUT>, OutputTypeConfigurable<OUT>, AsyncExceptionChecker

This is the operator that reads the FileInputSplits received from the preceding ContinuousFileMonitoringFunction. This operator can have parallelism greater than 1, contrary to the ContinuousFileMonitoringFunction which has a parallelism of 1.

This operator will receive the split descriptors, put them in a queue, and have another thread read the actual data from the split. This architecture allows the separation of the reading thread, from the one emitting the checkpoint barriers, thus removing any potential back-pressure.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

AbstractStreamOperator.CountingOutput

Field Summary

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

chainingStrategy, metrics, output

Constructor Summary

Constructors

Constructor and Description
ContinuousFileReaderOperator(org.apache.flink.api.common.io.FileInputFormat<OUT> format)

Method Summary

Modifier and Type	Method and Description
void	checkAsyncException() Checks if an asynchronous exception was thrown.
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.
void	open() This method is called immediately before any elements are processed, it should contain the operator's initialization logic.
void	processElement(StreamRecord<org.apache.flink.core.fs.FileInputSplit> element) Processes one element that arrived at this operator.
void	processWatermark(Watermark mark) Processes a Watermark.
void	restoreState(StreamTaskState state) Restores the operator state, if this operator's execution is recovering from a checkpoint.
void	setOutputType(org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outTypeInfo, org.apache.flink.api.common.ExecutionConfig executionConfig) Is called by the StreamGraph.addOperator(Integer, String, StreamOperator, TypeInformation, TypeInformation, String) method when the StreamGraph is generated.
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

getChainingStrategy, getContainingTask, getCurrentProcessingTime, getExecutionConfig, getMetricGroup, getOperatorConfig, getPartitionedState, getPartitionedState, getRuntimeContext, getStateBackend, getUserCodeClassloader, notifyOfCompletedCheckpoint, registerTimer, setChainingStrategy, setKeyContext, setKeyContextElement1, setKeyContextElement2, setup

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.streaming.api.operators.StreamOperator

getChainingStrategy, getMetricGroup, notifyOfCompletedCheckpoint, setChainingStrategy, setKeyContextElement1, setKeyContextElement2, setup

Constructor Detail

ContinuousFileReaderOperator

public ContinuousFileReaderOperator(org.apache.flink.api.common.io.FileInputFormat<OUT> format)

Method Detail

setOutputType

public void setOutputType(org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outTypeInfo,
                          org.apache.flink.api.common.ExecutionConfig executionConfig)

Description copied from interface: OutputTypeConfigurable

Is called by the StreamGraph.addOperator(Integer, String, 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

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.

processElement

public void processElement(StreamRecord<org.apache.flink.core.fs.FileInputSplit> element)
                    throws Exception

Description copied from interface: OneInputStreamOperator

Processes one element that arrived at this operator. This method is guaranteed to not be called concurrently with other methods of the operator.

Specified by:

processElement in interface OneInputStreamOperator<org.apache.flink.core.fs.FileInputSplit,OUT>

Throws:

Exception

processWatermark

public void processWatermark(Watermark mark)
                      throws Exception

Description copied from interface: OneInputStreamOperator

Processes a Watermark. This method is guaranteed to not be called concurrently with other methods of the operator.

Specified by:

processWatermark in interface OneInputStreamOperator<org.apache.flink.core.fs.FileInputSplit,OUT>

Throws:

Exception

See Also:

Watermark

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>

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.

checkAsyncException

public void checkAsyncException()

Description copied from interface: AsyncExceptionChecker

Checks if an asynchronous exception was thrown.

Specified by:

checkAsyncException in interface AsyncExceptionChecker

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 occurred).

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.