org.apache.hive.hcatalog.data.transfer

Class HCatWriter

java.lang.Object

org.apache.hive.hcatalog.data.transfer.HCatWriter

Direct Known Subclasses:

HCatOutputFormatWriter

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public abstract class HCatWriter
extends Object

This abstraction is internal to HCatalog. This is to facilitate writing to HCatalog from external systems. Don't try to instantiate this directly. Instead, use DataTransferFactory

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.hadoop.conf.Configuration	conf
protected WriterContext	info
protected StateProvider	sp
protected WriteEntity	we

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	HCatWriter(org.apache.hadoop.conf.Configuration config, StateProvider sp) This constructor will be used at slave nodes.
protected	HCatWriter(WriteEntity we, Map<String,String> config) This constructor will be used at master node

Method Summary

Modifier and Type	Method and Description
abstract void	abort(WriterContext context) This method should be called at master node.
abstract void	commit(WriterContext context) This method should be called at master node.
abstract WriterContext	prepareWrite() External system should invoke this method exactly once from a master node.
abstract void	write(Iterator<HCatRecord> recordItr) This method should be used at slave needs to perform writes.

Methods inherited from class java.lang.Object

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

Field Detail

conf

protected org.apache.hadoop.conf.Configuration conf

we

protected WriteEntity we

info

protected WriterContext info

sp

protected StateProvider sp

Constructor Detail

HCatWriter

protected HCatWriter(WriteEntity we,
                     Map<String,String> config)

This constructor will be used at master node

Parameters:

we - WriteEntity defines where in storage records should be written to.

config - Any configuration which external system wants to communicate to HCatalog for performing writes.

HCatWriter

protected HCatWriter(org.apache.hadoop.conf.Configuration config,
                     StateProvider sp)

This constructor will be used at slave nodes.

Parameters:

config -

Method Detail

prepareWrite

public abstract WriterContext prepareWrite()
                                    throws HCatException

External system should invoke this method exactly once from a master node.

Returns:

WriterContext This should be serialized and sent to slave nodes to construct HCatWriter there.

Throws:

HCatException

write

public abstract void write(Iterator<HCatRecord> recordItr)
                    throws HCatException

This method should be used at slave needs to perform writes.

Parameters:

recordItr - Iterator records to be written into HCatalog.

Throws:

{@link - HCatException}

HCatException

commit

public abstract void commit(WriterContext context)
                     throws HCatException

This method should be called at master node. Primary purpose of this is to do metadata commit.

Throws:

{@link - HCatException}

HCatException

abort

public abstract void abort(WriterContext context)
                    throws HCatException

This method should be called at master node. Primary purpose of this is to do cleanups in case of failures.

Throws:

{@link - HCatException} *

HCatException