org.apache.hadoop.hive.ql.exec.persistence
Class RowContainer<Row extends List<Object>>
java.lang.Object
org.apache.hadoop.hive.ql.exec.persistence.AbstractRowContainer<Row>
org.apache.hadoop.hive.ql.exec.persistence.RowContainer<Row>
public class RowContainer<Row extends List<Object>>
- extends AbstractRowContainer<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.
Field Summary |
protected static org.apache.commons.logging.Log |
LOG
|
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)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
LOG
protected static org.apache.commons.logging.Log LOG
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
setSerDe
public void setSerDe(SerDe sd,
ObjectInspector oi)
add
public void add(Row t)
throws HiveException
- Specified by:
add
in class AbstractRowContainer<Row extends List<Object>>
- Throws:
HiveException
first
public Row first()
throws HiveException
- Specified by:
first
in class AbstractRowContainer<Row extends List<Object>>
- Throws:
HiveException
next
public Row next()
throws HiveException
- Specified by:
next
in class AbstractRowContainer<Row extends List<Object>>
- Throws:
HiveException
size
public int size()
- Get the number of elements in the RowContainer.
- Specified by:
size
in class 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
clear
public void clear()
throws HiveException
- Remove all elements in the RowContainer.
- Specified by:
clear
in class AbstractRowContainer<Row extends List<Object>>
- Throws:
HiveException
setKeyObject
public void setKeyObject(List<Object> dummyKey)
setTableDesc
public void setTableDesc(TableDesc tblDesc)
Copyright © 2011 The Apache Software Foundation