Package org.apache.hadoop.util

Class QuickSort

java.lang.Object

org.apache.hadoop.util.QuickSort

All Implemented Interfaces:

IndexedSorter

@Private
@Unstable
public final class QuickSort
extends Object
implements IndexedSorter

An implementation of the core algorithm of QuickSort.

Constructor Summary

Constructors

Constructor	Description
QuickSort()

Method Summary

Modifier and Type	Method	Description
protected static int	getMaxDepth(int x)	Deepest recursion before giving up and doing a heapsort.
void	sort(IndexedSortable s, int p, int r)	Sort the given range of items using quick sort.
void	sort(IndexedSortable s, int p, int r, Progressable rep)	Same as IndexedSorter.sort(IndexedSortable,int,int), but indicate progress periodically.

Methods inherited from class java.lang.Object

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

Constructor Details

QuickSort

public QuickSort()

Method Details

getMaxDepth

protected static int getMaxDepth(int x)

Deepest recursion before giving up and doing a heapsort. Returns 2 * ceil(log(n)).

Parameters:

x - x.

Returns:

MaxDepth.

sort

public void sort(IndexedSortable s,
 int p,
 int r)

Sort the given range of items using quick sort. Sort the items accessed through the given IndexedSortable over the given range of logical indices. From the perspective of the sort algorithm, each index between l (inclusive) and r (exclusive) is an addressable entry. If the recursion depth falls below getMaxDepth(int), then switch to HeapSort.

Specified by:

sort in interface IndexedSorter

Parameters:

s - s.

p - l.

r - r.

See Also:

• IndexedSortable.compare(int, int)
• IndexedSortable.swap(int, int)

sort

public void sort(IndexedSortable s,
 int p,
 int r,
 Progressable rep)

Description copied from interface: IndexedSorter

Same as IndexedSorter.sort(IndexedSortable,int,int), but indicate progress periodically.

Specified by:

sort in interface IndexedSorter

Parameters:

s - s.

p - l.

r - r.

rep - rep.

See Also:

• IndexedSorter.sort(IndexedSortable,int,int)