org.apache.hadoop.dynamodb.read

Class AbstractDynamoDBRecordReader<K,V>

java.lang.Object

org.apache.hadoop.dynamodb.read.AbstractDynamoDBRecordReader<K,V>

Type Parameters:

K - The type of Key that will be passed to the Mapper

V - The type of Value that will be passed to the Mapper

All Implemented Interfaces:

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

Direct Known Subclasses:

DefaultDynamoDBRecordReader

public abstract class AbstractDynamoDBRecordReader<K,V>
extends Object
implements org.apache.hadoop.mapred.RecordReader<K,V>

AbstractDynamoDBRecordReader does all the backend work for splitting up the data in DynamoDB, reading it in, and outputting them into key-value pairs for the mapper. To use the DynamoDBRecordReader class, you need to subclass this and overwrite the convertDynamoDBItemToValue with a conversion from the DynamoDB item to the desired value type. As an alternative, you can also use DefaultDynamoDBRecordReader, and do the conversion to a DynamoDBItemWritable inside of the reducer.

Constructor Summary

Constructors

Constructor and Description
AbstractDynamoDBRecordReader(DynamoDBRecordReaderContext context)

Method Summary

Modifier and Type	Method and Description
void	close()
long	getPos()
float	getProgress()
boolean	next(K key, V value)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.mapred.RecordReader

createKey, createValue

Constructor Detail

AbstractDynamoDBRecordReader

public AbstractDynamoDBRecordReader(DynamoDBRecordReaderContext context)

Method Detail

getPos

public long getPos()
            throws IOException

Specified by:

getPos in interface org.apache.hadoop.mapred.RecordReader<K,V>

Throws:

IOException

getProgress

public float getProgress()
                  throws IOException

Specified by:

getProgress in interface org.apache.hadoop.mapred.RecordReader<K,V>

Throws:

IOException

next

public boolean next(K key,
                    V value)
             throws IOException

Specified by:

next in interface org.apache.hadoop.mapred.RecordReader<K,V>

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface org.apache.hadoop.mapred.RecordReader<K,V>

Throws:

IOException