org.apache.carbondata.hadoop.readsupport.impl

Class DictionaryDecodeReadSupport<T>

java.lang.Object

org.apache.carbondata.hadoop.readsupport.impl.DictionaryDecodeReadSupport<T>

All Implemented Interfaces:

CarbonReadSupport<T>

Direct Known Subclasses:

CarbonRowReadSupport

public class DictionaryDecodeReadSupport<T>
extends Object
implements CarbonReadSupport<T>

This is the class to decode dictionary encoded column data back to its original value.

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.carbondata.core.metadata.schema.table.column.CarbonColumn[]	carbonColumns carbon columns
protected org.apache.carbondata.core.metadata.datatype.DataType[]	dataTypes
protected org.apache.carbondata.core.cache.dictionary.Dictionary[]	dictionaries

Constructor Summary

Constructors

Constructor and Description
DictionaryDecodeReadSupport()

Method Summary

Modifier and Type	Method and Description
void	close() to book keep the dictionary cache or update access count for each column involved during decode, to facilitate LRU cache policy if memory threshold is reached
void	initialize(org.apache.carbondata.core.metadata.schema.table.column.CarbonColumn[] carbonColumns, org.apache.carbondata.core.metadata.schema.table.CarbonTable carbonTable) This initialization is done inside executor task for column dictionary involved in decoding.
T	readRow(Object[] data) convert column data back to row representation

Methods inherited from class java.lang.Object

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

Field Detail

dictionaries

protected org.apache.carbondata.core.cache.dictionary.Dictionary[] dictionaries

dataTypes

protected org.apache.carbondata.core.metadata.datatype.DataType[] dataTypes

carbonColumns

protected org.apache.carbondata.core.metadata.schema.table.column.CarbonColumn[] carbonColumns

carbon columns

Constructor Detail

DictionaryDecodeReadSupport

public DictionaryDecodeReadSupport()

Method Detail

initialize

public void initialize(org.apache.carbondata.core.metadata.schema.table.column.CarbonColumn[] carbonColumns,
                       org.apache.carbondata.core.metadata.schema.table.CarbonTable carbonTable)
                throws IOException

This initialization is done inside executor task for column dictionary involved in decoding.

Specified by:

initialize in interface CarbonReadSupport<T>

Parameters:

carbonColumns - column list

carbonTable - table identifier

Throws:

IOException

readRow

public T readRow(Object[] data)

Description copied from interface: CarbonReadSupport

convert column data back to row representation

Specified by:

readRow in interface CarbonReadSupport<T>

Parameters:

data - column data

close

public void close()

to book keep the dictionary cache or update access count for each column involved during decode, to facilitate LRU cache policy if memory threshold is reached

Specified by:

close in interface CarbonReadSupport<T>