org.apache.flink.api.java.hadoop.mapred

Class HadoopInputFormatBase<K,V,T>

java.lang.Object

org.apache.flink.api.common.io.RichInputFormat<T,SPITTYPE>

org.apache.flink.api.java.hadoop.common.HadoopInputFormatCommonBase<T,HadoopInputSplit>

org.apache.flink.api.java.hadoop.mapred.HadoopInputFormatBase<K,V,T>

Type Parameters:

K - Type of key

V - Type of value

T - The type itself

All Implemented Interfaces:

Serializable, InputFormat<T,HadoopInputSplit>, InputSplitSource<HadoopInputSplit>

Direct Known Subclasses:

HadoopInputFormat

@Internal
public abstract class HadoopInputFormatBase<K,V,T>
extends HadoopInputFormatCommonBase<T,HadoopInputSplit>

Common base for Java and Scala API for using Hadoop input formats with Flink.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	fetched
protected boolean	hasNext
protected K	key
protected Class<K>	keyClass
protected V	value
protected Class<V>	valueClass

Fields inherited from class org.apache.flink.api.java.hadoop.common.HadoopInputFormatCommonBase

credentials

Constructor Summary

Constructors

Constructor and Description
HadoopInputFormatBase(org.apache.hadoop.mapred.InputFormat<K,V> mapredInputFormat, Class<K> key, Class<V> value, org.apache.hadoop.mapred.JobConf job)

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.
HadoopInputSplit[]	createInputSplits(int minNumSplits) Computes the input splits.
protected void	fetchNext()
InputSplitAssigner	getInputSplitAssigner(HadoopInputSplit[] inputSplits) Returns the assigner for the input splits.
org.apache.hadoop.mapred.JobConf	getJobConf()
BaseStatistics	getStatistics(BaseStatistics cachedStats) Gets the basic statistics from the input described by this format.
void	open(HadoopInputSplit 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.java.hadoop.common.HadoopInputFormatCommonBase

getCredentialsFromUGI, read, write

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

Methods inherited from interface org.apache.flink.api.common.io.InputFormat

nextRecord

Field Detail

keyClass

protected Class<K> keyClass

valueClass

protected Class<V> valueClass

key

protected transient K key

value

protected transient V value

fetched

protected transient boolean fetched

hasNext

protected transient boolean hasNext

Constructor Detail

HadoopInputFormatBase

public HadoopInputFormatBase(org.apache.hadoop.mapred.InputFormat<K,V> mapredInputFormat,
                             Class<K> key,
                             Class<V> value,
                             org.apache.hadoop.mapred.JobConf job)

Method Detail

getJobConf

public org.apache.hadoop.mapred.JobConf getJobConf()

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 cachedStats)
                             throws IOException

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:

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

Returns:

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

Throws:

IOException

createInputSplits

public HadoopInputSplit[] createInputSplits(int minNumSplits)
                                     throws IOException

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.

Throws:

IOException

getInputSplitAssigner

public InputSplitAssigner getInputSplitAssigner(HadoopInputSplit[] 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.

open

public void open(HadoopInputSplit 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.

reachedEnd

public boolean reachedEnd()
                   throws IOException

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.

Throws:

IOException - Thrown, if an I/O error occurred.

fetchNext

protected void fetchNext()
                  throws IOException

Throws:

IOException

close

public void close()
           throws IOException

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.

Throws:

IOException - Thrown, if the input could not be closed properly.