org.apache.hadoop.hive.ql.exec.persistence
Class RowContainer<Row extends List>
java.lang.Object
org.apache.hadoop.hive.ql.exec.persistence.RowContainer<Row>
public class RowContainer<Row extends List>
- extends Object
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 iterface.
Itereator 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
}
The adding and iterating operations can be interleaving.
Field Summary |
protected org.apache.commons.logging.Log |
LOG
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
LOG
protected org.apache.commons.logging.Log LOG
RowContainer
public RowContainer()
RowContainer
public RowContainer(int blockSize)
RowContainer
public RowContainer(int blockSize,
SerDe sd,
ObjectInspector oi)
setSerDe
public void setSerDe(SerDe sd,
ObjectInspector oi)
add
public void add(Row t)
throws HiveException
- Throws:
HiveException
first
public Row first()
next
public Row next()
size
public int size()
- Get the number of elements in the RowContainer.
- Returns:
- number of elements in the RowContainer
clear
public void clear()
throws HiveException
- Remove all elements in the RowContainer.
- Throws:
HiveException
setTableDesc
public void setTableDesc(tableDesc tblDesc)
Copyright © 2009 The Apache Software Foundation