org.apache.tez.runtime.library.utils

Class Grouper

java.lang.Object

org.apache.tez.runtime.library.utils.Grouper

public class Grouper
extends Object

This grouper group specified number of items into specified number of groups. If numItem%numGroup is zero, every group has numItem/numGroup items. Otherwise, every group will get numItem/numGroup items first, and remaining items will be distributed in last numItem-numItem%numGroup*numGroup groups (one item for each group). For example, if we group 8 items into 3 groups, each group get {2, 3, 3} items.

Constructor Summary

Constructors

Constructor and Description
Grouper()

Method Summary

Modifier and Type	Method and Description
int	getFirstItemInGroup(int groupId)
int	getGroupId(int itemId)
int	getLastItemInGroup(int groupId)
int	getNumItemsInGroup(int groupId)
Grouper	init(int numItem, int numGroup)
boolean	isInGroup(int itemId, int groupId)

Methods inherited from class java.lang.Object

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

Constructor Detail

Grouper

public Grouper()

Method Detail

init

public Grouper init(int numItem,
                    int numGroup)

getFirstItemInGroup

public int getFirstItemInGroup(int groupId)

getNumItemsInGroup

public int getNumItemsInGroup(int groupId)

getLastItemInGroup

public int getLastItemInGroup(int groupId)

getGroupId

public int getGroupId(int itemId)

isInGroup

public boolean isInGroup(int itemId,
                         int groupId)