org.apache.flink.state.api.input

Class ListStateInputFormat<OT>

java.lang.Object

org.apache.flink.api.common.io.RichInputFormat<OT,OperatorStateInputSplit>

org.apache.flink.state.api.input.ListStateInputFormat<OT>

Type Parameters:

OT - The generic type of the state

All Implemented Interfaces:

Serializable, InputFormat<OT,OperatorStateInputSplit>, InputSplitSource<OperatorStateInputSplit>

@Internal
public class ListStateInputFormat<OT>
extends RichInputFormat<OT,OperatorStateInputSplit>

Input format for reading operator list state.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ListStateInputFormat(OperatorState operatorState, Configuration configuration, StateBackend backend, ListStateDescriptor<OT> descriptor) Creates an input format for reading list state from an operator in a savepoint.

Method Summary

Modifier and Type	Method and Description
void	close() Method that marks the end of the life-cycle of an input split.
void	configure(Configuration parameters) Configures this input format.
OperatorStateInputSplit[]	createInputSplits(int minNumSplits) Computes the input splits.
protected Iterable<OT>	getElements(OperatorStateBackend restoredBackend)
InputSplitAssigner	getInputSplitAssigner(OperatorStateInputSplit[] inputSplits) Returns the assigner for the input splits.
BaseStatistics	getStatistics(BaseStatistics cachedStatistics) Gets the basic statistics from the input described by this format.
OT	nextRecord(OT reuse) Reads the next record from the input.
void	open(OperatorStateInputSplit split) Opens a parallel instance of the input format to work on a split.
boolean	reachedEnd() Method used to check if the end of the input is reached.

Methods inherited from class org.apache.flink.api.common.io.RichInputFormat

closeInputFormat, getRuntimeContext, openInputFormat, setRuntimeContext

Methods inherited from class java.lang.Object

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

Constructor Detail

ListStateInputFormat

public ListStateInputFormat(OperatorState operatorState,
                            Configuration configuration,
                            @Nullable
                            StateBackend backend,
                            ListStateDescriptor<OT> descriptor)

Creates an input format for reading list state from an operator in a savepoint.

Parameters:

operatorState - The state to be queried.

configuration - The cluster configuration for restoring the backend.

backend - The state backend used to restore the state.

descriptor - The descriptor for this state, providing a name and serializer.

Method Detail

getElements

protected final Iterable<OT> getElements(OperatorStateBackend restoredBackend)
                                  throws Exception

Throws:

Exception

configure

public void configure(Configuration parameters)

Description copied from interface: InputFormat

Configures this input format. Since input formats are instantiated generically and hence parameterless, this method is the place where the input formats set their basic fields based on configuration values.

This method is always called first on a newly instantiated input format.

Parameters:

parameters - The configuration with all parameters (note: not the Flink config but the TaskConfig).

getStatistics

public BaseStatistics getStatistics(BaseStatistics cachedStatistics)

Description copied from interface: InputFormat

Gets the basic statistics from the input described by this format. If the input format does not know how to create those statistics, it may return null. This method optionally gets a cached version of the statistics. The input format may examine them and decide whether it directly returns them without spending effort to re-gather the statistics.

When this method is called, the input format is guaranteed to be configured.

Parameters:

cachedStatistics - The statistics that were cached. May be null.

Returns:

The base statistics for the input, or null, if not available.

getInputSplitAssigner

public InputSplitAssigner getInputSplitAssigner(OperatorStateInputSplit[] inputSplits)

Description copied from interface: InputSplitSource

Returns the assigner for the input splits. Assigner determines which parallel instance of the input format gets which input split.

Returns:

The input split assigner.

createInputSplits

public OperatorStateInputSplit[] createInputSplits(int minNumSplits)

Description copied from interface: InputSplitSource

Computes the input splits. The given minimum number of splits is a hint as to how many splits are desired.

Parameters:

minNumSplits - Number of minimal input splits, as a hint.

Returns:

An array of input splits.

open

public void open(OperatorStateInputSplit split)
          throws IOException

Description copied from interface: InputFormat

Opens a parallel instance of the input format to work on a split.

When this method is called, the input format it guaranteed to be configured.

Parameters:

split - The split to be opened.

Throws:

IOException - Thrown, if the spit could not be opened due to an I/O problem.

close

public void close()

Description copied from interface: InputFormat

Method that marks the end of the life-cycle of an input split. Should be used to close channels and streams and release resources. After this method returns without an error, the input is assumed to be correctly read.

When this method is called, the input format it guaranteed to be opened.

reachedEnd

public boolean reachedEnd()

Description copied from interface: InputFormat

Method used to check if the end of the input is reached.

When this method is called, the input format it guaranteed to be opened.

Returns:

True if the end is reached, otherwise false.

nextRecord

public OT nextRecord(OT reuse)

Description copied from interface: InputFormat

Reads the next record from the input.

When this method is called, the input format it guaranteed to be opened.

Parameters:

reuse - Object that may be reused.

Returns:

Read record.