org.apache.avro.mapreduce

Class AvroRecordReaderBase<K,V,T>

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<K,V>

org.apache.avro.mapreduce.AvroRecordReaderBase<K,V,T>

Type Parameters:

K - The type of key the record reader should generate.

V - The type of value the record reader should generate.

T - The type of the entries within the Avro container file being read.

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

AvroKeyRecordReader, AvroKeyValueRecordReader

public abstract class AvroRecordReaderBase<K,V,T>
extends RecordReader<K,V>

Abstract base class for RecordReaders that read Avro container files.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AvroRecordReaderBase(Schema readerSchema) Constructor.

Method Summary

Modifier and Type	Method and Description
void	close()
protected DataFileReader<T>	createAvroFileReader(SeekableInput input, DatumReader<T> datumReader) Creates an Avro container file reader from a seekable input stream.
protected SeekableInput	createSeekableInput(Configuration conf, Path path) Creates a seekable input stream to an Avro container file.
protected T	getCurrentRecord() Gets the current record read from the Avro container file.
float	getProgress()
void	initialize(InputSplit inputSplit, TaskAttemptContext context)
boolean	nextKeyValue()

Methods inherited from class org.apache.hadoop.mapreduce.RecordReader

getCurrentKey, getCurrentValue

Methods inherited from class java.lang.Object

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

Constructor Detail

AvroRecordReaderBase

protected AvroRecordReaderBase(Schema readerSchema)

Constructor.

Parameters:

readerSchema - The reader schema for the records of the Avro container file.

Method Detail

initialize

public void initialize(InputSplit inputSplit,
                       TaskAttemptContext context)
                throws IOException,
                       InterruptedException

Specified by:

initialize in class RecordReader<K,V>

Throws:

IOException

InterruptedException

nextKeyValue

public boolean nextKeyValue()
                     throws IOException,
                            InterruptedException

Specified by:

nextKeyValue in class RecordReader<K,V>

Throws:

IOException

InterruptedException

getProgress

public float getProgress()
                  throws IOException,
                         InterruptedException

Specified by:

getProgress in class RecordReader<K,V>

Throws:

IOException

InterruptedException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class RecordReader<K,V>

Throws:

IOException

getCurrentRecord

protected T getCurrentRecord()

Gets the current record read from the Avro container file.

Calling nextKeyValue() moves this to the next record.

Returns:

The current Avro record (may be null if no record has been read).

createSeekableInput

protected SeekableInput createSeekableInput(Configuration conf,
                                            Path path)
                                     throws IOException

Creates a seekable input stream to an Avro container file.

Parameters:

conf - The hadoop configuration.

path - The path to the avro container file.

Throws:

IOException - If there is an error reading from the path.

createAvroFileReader

protected DataFileReader<T> createAvroFileReader(SeekableInput input,
                                                 DatumReader<T> datumReader)
                                          throws IOException

Creates an Avro container file reader from a seekable input stream.

Parameters:

input - The input containing the Avro container file.

datumReader - The reader to use for the individual records in the Avro container file.

Throws:

IOException - If there is an error reading from the input stream.