com.facebook.presto.spi.function

Class RankingWindowFunction

java.lang.Object

com.facebook.presto.spi.function.RankingWindowFunction

All Implemented Interfaces:

WindowFunction

public abstract class RankingWindowFunction
extends Object
implements WindowFunction

Field Summary

Fields

Modifier and Type	Field and Description
protected WindowIndex	windowIndex

Constructor Summary

Constructors

Constructor and Description
RankingWindowFunction()

Method Summary

Modifier and Type	Method and Description
abstract void	processRow(BlockBuilder output, boolean newPeerGroup, int peerGroupCount, int currentPosition) Process a row by outputting the result of the window function.
void	processRow(BlockBuilder output, int peerGroupStart, int peerGroupEnd, int frameStart, int frameEnd) Process a row by outputting the result of the window function.
void	reset() Reset state for a new partition (including the first one).
void	reset(WindowIndex windowIndex) Reset state for a new partition (including the first one).

Methods inherited from class java.lang.Object

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

Field Detail

windowIndex

protected WindowIndex windowIndex

Constructor Detail

RankingWindowFunction

public RankingWindowFunction()

Method Detail

reset

public final void reset(WindowIndex windowIndex)

Description copied from interface: WindowFunction

Reset state for a new partition (including the first one).

Specified by:

reset in interface WindowFunction

Parameters:

windowIndex - the window index which contains sorted values for the partition

processRow

public final void processRow(BlockBuilder output,
                             int peerGroupStart,
                             int peerGroupEnd,
                             int frameStart,
                             int frameEnd)

Description copied from interface: WindowFunction

Process a row by outputting the result of the window function.

This method provides information about the ordering peer group. A peer group is all of the rows that are peers within the specified ordering. Rows are peers if they compare equal to each other using the specified ordering expression. The ordering of rows within a peer group is undefined (otherwise they would not be peers).

Specified by:

processRow in interface WindowFunction

Parameters:

output - the BlockBuilder to use for writing the output row

peerGroupStart - the position of the first row in the peer group

peerGroupEnd - the position of the last row in the peer group

frameStart - the position of the first row in the window frame

frameEnd - the position of the last row in the window frame

reset

public void reset()

Reset state for a new partition (including the first one).

processRow

public abstract void processRow(BlockBuilder output,
                                boolean newPeerGroup,
                                int peerGroupCount,
                                int currentPosition)

Process a row by outputting the result of the window function.

This method provides information about the ordering peer group. A peer group is all of the rows that are peers within the specified ordering. Rows are peers if they compare equal to each other using the specified ordering expression. The ordering of rows within a peer group is undefined (otherwise they would not be peers).

Parameters:

output - the BlockBuilder to use for writing the output row

newPeerGroup - if this row starts a new peer group

peerGroupCount - the total number of rows in this peer group

currentPosition - the current position for this row