net.sf.cglib.util
Class ParallelSorter
java.lang.Object
net.sf.cglib.util.SorterTemplate
net.sf.cglib.util.ParallelSorter
public abstract class ParallelSorter
extends net.sf.cglib.util.SorterTemplate
For the efficient sorting of multiple arrays in parallel.
Given two arrays of equal length and varying types, the standard
technique for sorting them in parallel is to create a new temporary
object for each row, store the objects in a temporary array, sort the
array using a custom comparator, and the extract the original values
back into their respective arrays. This is wasteful in both time and
memory.
This class generates bytecode customized to the particular set of
arrays you need to sort, in such a way that both arrays are sorted
in-place, simultaneously.
Two sorting algorithms are provided.
Quicksort is best when you only need to sort by a single column, as
it requires very few comparisons and swaps. Mergesort is best used
when sorting multiple columns, as it is a "stable" sort--that is, it
does not affect the relative order of equal objects from previous sorts.
The mergesort algorithm here is an "in-place" variant, which while
slower, does not require a temporary array.
static ParallelSorter | create(Object[] arrays) - Create a new ParallelSorter object for a set of arrays.
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void | mergeSort(int index)
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void | mergeSort(int index, Comparator cmp) - Sort the arrays using an in-place merge sort.
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void | mergeSort(int index, int lo, int hi) - Sort the arrays using an in-place merge sort.
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void | mergeSort(int index, int lo, int hi, Comparator cmp) - Sort the arrays using an in-place merge sort.
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abstract ParallelSorter | newInstance(Object[] arrays)
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void | quickSort(int index) - Sort the arrays using the quicksort algorithm.
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void | quickSort(int index, Comparator cmp) - Sort the arrays using the quicksort algorithm.
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void | quickSort(int index, int lo, int hi) - Sort the arrays using the quicksort algorithm.
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void | quickSort(int index, int lo, int hi, Comparator cmp) - Sort the arrays using the quicksort algorithm.
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create
public static ParallelSorter create(Object[] arrays)
Create a new ParallelSorter object for a set of arrays. You may
sort the arrays multiple times via the same ParallelSorter object.
arrays
- An array of arrays to sort. The arrays may be a mix
of primitive and non-primitive types, but should all be the same
length.
mergeSort
public void mergeSort(int index)
index
- array (column) to sort by
mergeSort
public void mergeSort(int index,
Comparator cmp)
Sort the arrays using an in-place merge sort.
index
- array (column) to sort by
mergeSort
public void mergeSort(int index,
int lo,
int hi)
Sort the arrays using an in-place merge sort.
index
- array (column) to sort bylo
- starting array index (row), inclusivehi
- ending array index (row), exclusive
mergeSort
public void mergeSort(int index,
int lo,
int hi,
Comparator cmp)
Sort the arrays using an in-place merge sort.
index
- array (column) to sort bylo
- starting array index (row), inclusivehi
- ending array index (row), exclusivecmp
- Comparator to use if the specified column is non-primitive
newInstance
public abstract ParallelSorter newInstance(Object[] arrays)
quickSort
public void quickSort(int index)
Sort the arrays using the quicksort algorithm.
index
- array (column) to sort by
quickSort
public void quickSort(int index,
Comparator cmp)
Sort the arrays using the quicksort algorithm.
index
- array (column) to sort bycmp
- Comparator to use if the specified column is non-primitive
quickSort
public void quickSort(int index,
int lo,
int hi)
Sort the arrays using the quicksort algorithm.
index
- array (column) to sort bylo
- starting array index (row), inclusivehi
- ending array index (row), exclusive
quickSort
public void quickSort(int index,
int lo,
int hi,
Comparator cmp)
Sort the arrays using the quicksort algorithm.
index
- array (column) to sort bylo
- starting array index (row), inclusivehi
- ending array index (row), exclusivecmp
- Comparator to use if the specified column is non-primitive
Copyright (c) 2001 - Apache Software Foundation