org.apache.lucene.util

Class TimSorter

java.lang.Object

org.apache.lucene.util.Sorter

org.apache.lucene.util.TimSorter

public abstract class TimSorter
extends Sorter

Sorter implementation based on the TimSort algorithm.

This implementation is especially good at sorting partially-sorted arrays and sorts small arrays with binary sort.

NOTE:There are a few differences with the original implementation:

• The extra amount of memory to perform merges is configurable. This allows small merges to be very fast while large merges will be performed in-place (slightly slower). You can make sure that the fast merge routine will always be used by having maxTempSlots equal to half of the length of the slice of data to sort.
• Only the fast merge routine can gallop (the one that doesn't run in-place) and it only gallops on the longest slice.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TimSorter(int maxTempSlots) Create a new TimSorter.

Method Summary

Modifier and Type	Method and Description
protected abstract int	compareSaved(int i, int j) Compare element i from the temporary storage with element j from the slice to sort, similarly to Sorter.compare(int, int).
protected abstract void	copy(int src, int dest) Copy data from slot src to slot dest.
protected abstract void	restore(int i, int j) Restore element j from the temporary storage into slot i.
protected abstract void	save(int i, int len) Save all elements between slots i and i+len into the temporary storage.
void	sort(int from, int to) Sort the slice which starts at from (inclusive) and ends at to (exclusive).

Methods inherited from class org.apache.lucene.util.Sorter

compare, swap

Methods inherited from class java.lang.Object

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

Constructor Detail

TimSorter

protected TimSorter(int maxTempSlots)

Create a new TimSorter.

Parameters:

maxTempSlots - the maximum amount of extra memory to run merges

Method Detail

sort

public void sort(int from,
                 int to)

Description copied from class: Sorter

Sort the slice which starts at from (inclusive) and ends at to (exclusive).

Specified by:

sort in class Sorter

copy

protected abstract void copy(int src,
                             int dest)

Copy data from slot src to slot dest.

save

protected abstract void save(int i,
                             int len)

Save all elements between slots i and i+len into the temporary storage.

restore

protected abstract void restore(int i,
                                int j)

Restore element j from the temporary storage into slot i.

compareSaved

protected abstract int compareSaved(int i,
                                    int j)

Compare element i from the temporary storage with element j from the slice to sort, similarly to Sorter.compare(int, int).