org.apache.hadoop.hive.ql.exec.persistence
Class RowContainer<ROW extends List<Object>>

java.lang.Object
  org.apache.hadoop.hive.ql.exec.persistence.RowContainer<ROW>

All Implemented Interfaces:

AbstractRowContainer<ROW>, AbstractRowContainer.RowIterator<ROW>

Direct Known Subclasses:

PTFRowContainer

public class RowContainer<ROW extends List<Object>>
extends Object
implements AbstractRowContainer<ROW>, AbstractRowContainer.RowIterator<ROW>

Simple persistent container for rows. This container interface only accepts adding or appending new rows and iterating through the rows in the order of their insertions. The iterator interface is a lightweight first()/next() API rather than the Java Iterator interface. This way we do not need to create an Iterator object every time we want to start a new iteration. Below is simple example of how to convert a typical Java's Iterator code to the LW iterator interface. Iterator itr = rowContainer.iterator(); while (itr.hasNext()) { v = itr.next(); // do anything with v } can be rewritten to: for ( v = rowContainer.first(); v != null; v = rowContainer.next()) { // do anything with v } Once the first is called, it will not be able to write again. So there can not be any writes after read. It can be read multiple times, but it does not support multiple reader interleaving reading.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hive.ql.exec.persistence.AbstractRowContainer

AbstractRowContainer.RowIterator<ROW>

Constructor Summary

RowContainer(org.apache.hadoop.conf.Configuration jc, org.apache.hadoop.mapred.Reporter reporter)

RowContainer(int bs, org.apache.hadoop.conf.Configuration jc, org.apache.hadoop.mapred.Reporter reporter)

Method Summary

void	addRow(ROW t) add a row into the RowContainer
void	clearRows() Remove all elements in the RowContainer.
void	copyToDFSDirecory(org.apache.hadoop.fs.FileSystem destFs, org.apache.hadoop.fs.Path destPath)
ROW	first()
ROW	next()
int	rowCount() Get the number of elements in the RowContainer.
AbstractRowContainer.RowIterator<ROW>	rowIter()
void	setKeyObject(List<Object> dummyKey)
void	setSerDe(SerDe sd, ObjectInspector oi)
void	setTableDesc(TableDesc tblDesc)

Methods inherited from class java.lang.Object

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

Constructor Detail

RowContainer

public RowContainer(org.apache.hadoop.conf.Configuration jc,
                    org.apache.hadoop.mapred.Reporter reporter)
             throws HiveException

Throws:

HiveException

RowContainer

public RowContainer(int bs,
                    org.apache.hadoop.conf.Configuration jc,
                    org.apache.hadoop.mapred.Reporter reporter)
             throws HiveException

Throws:

HiveException

Method Detail

setSerDe

public void setSerDe(SerDe sd,
                     ObjectInspector oi)

addRow

public void addRow(ROW t)
            throws HiveException

Description copied from interface: AbstractRowContainer

add a row into the RowContainer

Specified by:

addRow in interface AbstractRowContainer<ROW extends List<Object>>

Parameters:

t - row

Throws:

HiveException

rowIter

public AbstractRowContainer.RowIterator<ROW> rowIter()

Specified by:

rowIter in interface AbstractRowContainer<ROW extends List<Object>>

first

public ROW first()
                               throws HiveException

Specified by:

first in interface AbstractRowContainer.RowIterator<ROW extends List<Object>>

Throws:

HiveException

next

public ROW next()
                              throws HiveException

Specified by:

next in interface AbstractRowContainer.RowIterator<ROW extends List<Object>>

Throws:

HiveException

rowCount

public int rowCount()

Get the number of elements in the RowContainer.

Specified by:

rowCount in interface AbstractRowContainer<ROW extends List<Object>>

Returns:

number of elements in the RowContainer

copyToDFSDirecory

public void copyToDFSDirecory(org.apache.hadoop.fs.FileSystem destFs,
                              org.apache.hadoop.fs.Path destPath)
                       throws IOException,
                              HiveException

Throws:

IOException

HiveException

clearRows

public void clearRows()
               throws HiveException

Remove all elements in the RowContainer.

Specified by:

clearRows in interface AbstractRowContainer<ROW extends List<Object>>

Throws:

HiveException

setKeyObject

public void setKeyObject(List<Object> dummyKey)

setTableDesc

public void setTableDesc(TableDesc tblDesc)