com.uwyn.jhighlight.fastutil

クラス Arrays

java.lang.Object

com.uwyn.jhighlight.fastutil.Arrays

public class Arrays
extends Object

A class providing static methods and objects that do useful things with arrays.

In addition to commodity methods, this class contains Swapper-based implementations of quicksort and of a stable, in-place mergesort. These generic sorting methods can be used to sort any kind of list, but they find their natural usage, for instance, in sorting arrays in parallel.

関連項目:

Arrays

フィールドの概要

フィールド

修飾子とタイプ	フィールドと説明
static int	MAX_ARRAY_SIZE This is a safe value used by ArrayList (as of Java 7) to avoid throwing OutOfMemoryError on some JVMs.

メソッドの概要

メソッド

修飾子とタイプ	メソッドと説明
static void	ensureFromTo(int arrayLength, int from, int to) Ensures that a range given by its first (inclusive) and last (exclusive) elements fits an array of given length.
static void	ensureOffsetLength(int arrayLength, int offset, int length) Ensures that a range given by an offset and a length fits an array of given length.
static void	mergeSort(int from, int to, IntComparator c, Swapper swapper) Sorts the specified range of elements using the specified swapper and according to the order induced by the specified comparator using mergesort.
static void	quickSort(int from, int to, IntComparator comp, Swapper swapper) Sorts the specified range of elements using the specified swapper and according to the order induced by the specified comparator using quicksort.

クラスから継承されたメソッド java.lang.Object

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

フィールドの詳細

MAX_ARRAY_SIZE

public static final int MAX_ARRAY_SIZE

This is a safe value used by ArrayList (as of Java 7) to avoid throwing OutOfMemoryError on some JVMs. We adopt the same value.

関連項目:

定数フィールド値

メソッドの詳細

ensureFromTo

public static void ensureFromTo(int arrayLength,
                int from,
                int to)

Ensures that a range given by its first (inclusive) and last (exclusive) elements fits an array of given length.

This method may be used whenever an array range check is needed.

パラメータ:

arrayLength - an array length.

from - a start index (inclusive).

to - an end index (inclusive).

例外:

IllegalArgumentException - if from is greater than to.

ArrayIndexOutOfBoundsException - if from or to are greater than arrayLength or negative.

ensureOffsetLength

public static void ensureOffsetLength(int arrayLength,
                      int offset,
                      int length)

Ensures that a range given by an offset and a length fits an array of given length.

This method may be used whenever an array range check is needed.

パラメータ:

arrayLength - an array length.

offset - a start index for the fragment

length - a length (the number of elements in the fragment).

例外:

IllegalArgumentException - if length is negative.

ArrayIndexOutOfBoundsException - if offset is negative or offset+length is greater than arrayLength.

mergeSort

public static void mergeSort(int from,
             int to,
             IntComparator c,
             Swapper swapper)

Sorts the specified range of elements using the specified swapper and according to the order induced by the specified comparator using mergesort.

This sort is guaranteed to be stable: equal elements will not be reordered as a result of the sort. The sorting algorithm is an in-place mergesort that is significantly slower than a standard mergesort, as its running time is O(n (log n)²), but it does not allocate additional memory; as a result, it can be used as a generic sorting algorithm.

パラメータ:

from - the index of the first element (inclusive) to be sorted.

to - the index of the last element (exclusive) to be sorted.

c - the comparator to determine the order of the generic data (arguments are positions).

swapper - an object that knows how to swap the elements at any two positions.

quickSort

public static void quickSort(int from,
             int to,
             IntComparator comp,
             Swapper swapper)

Sorts the specified range of elements using the specified swapper and according to the order induced by the specified comparator using quicksort.

The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.

パラメータ:

from - the index of the first element (inclusive) to be sorted.

to - the index of the last element (exclusive) to be sorted.

comp - the comparator to determine the order of the generic data.

swapper - an object that knows how to swap the elements at any two positions.