org.datavec.hadoop.records.reader.mapfile

Interface IndexToKey

All Known Implementing Classes:

LongIndexToKey

public interface IndexToKey

An interface to handle Index to key conversion, for use in MapFileReader

Author:

Alex Black

Method Summary

Modifier and Type	Method and Description
org.apache.hadoop.io.WritableComparable	getKeyForIndex(long index) Get the key for the given index
long	getNumRecords() Getter infer the number of records in the given map file(s)
List<org.nd4j.linalg.primitives.Pair<Long,Long>>	initialize(org.apache.hadoop.io.MapFile.Reader[] readers, Class<? extends org.apache.hadoop.io.Writable> valueClass) Initialise the instance, and return the first and last record indexes (inclusive) for each reader

Method Detail

initialize

List<org.nd4j.linalg.primitives.Pair<Long,Long>> initialize(org.apache.hadoop.io.MapFile.Reader[] readers,
                                                            Class<? extends org.apache.hadoop.io.Writable> valueClass)
                                                     throws IOException

Initialise the instance, and return the first and last record indexes (inclusive) for each reader

Parameters:

readers - The underlying map file readers

Throws:

IOException

getKeyForIndex

org.apache.hadoop.io.WritableComparable getKeyForIndex(long index)

Get the key for the given index

Parameters:

index - 0 to getNumRecords(reader)

Returns:

The key for the given index

getNumRecords

long getNumRecords()
            throws IOException

Getter infer the number of records in the given map file(s)

Returns:

Number of records in the map file(s)

Throws:

IOException