Package com.github.tommyettinger.ds.support.sort

Class ObjectComparators

java.lang.Object

com.github.tommyettinger.ds.support.sort.ObjectComparators

public final class ObjectComparators
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	ObjectComparators.NaturalImplicitComparator<T extends Comparable<? super T>>	A type-specific comparator mimicking the natural order.
protected static class	ObjectComparators.OppositeComparator<T>
protected static class	ObjectComparators.OppositeImplicitComparator<T extends Comparable<? super T>>	A type-specific comparator mimicking the opposite of the natural order.

Field Summary

Fields

Modifier and Type	Field	Description
static final Comparator<?>	NATURAL_COMPARATOR
static final Comparator<?>	OPPOSITE_COMPARATOR

Method Summary

Modifier and Type	Method	Description
static <T> Comparator<T>	comparingFloat(com.github.tommyettinger.function.ObjToFloatFunction<? super T> keyExtractor)	Accepts a function that extracts a float sort key from a type T, and returns a Comparator<T> that compares by that sort key.
static <T> Comparator<T>	oppositeComparator(Comparator<T> c)	Returns a comparator representing the opposite order of the given comparator.
static <K> void	sort(List<K> items, int from, int to, Comparator<? super K> c)	Sorts the specified range of elements according to the order induced by the specified comparator using mergesort.
static <K> void	sort(List<K> items, Comparator<? super K> c)	Sorts all of items by simply calling sort(List, int, int, Comparator) setting from and to so the whole array is sorted.
static <K> void	sort(K[] items, int from, int to, Comparator<? super K> c)	Sorts the specified range of elements according to the order induced by the specified comparator using mergesort.
static <K> void	sort(K[] items, Comparator<? super K> c)	Sorts all of items by simply calling sort(List, int, int, Comparator) setting from and to so the whole array is sorted.

Methods inherited from class java.lang.Object

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

Field Details

NATURAL_COMPARATOR

public static final Comparator<?> NATURAL_COMPARATOR

OPPOSITE_COMPARATOR

public static final Comparator<?> OPPOSITE_COMPARATOR

Method Details

oppositeComparator

public static <T> Comparator<T> oppositeComparator(Comparator<T> c)

Returns a comparator representing the opposite order of the given comparator.

Parameters:

c - a comparator.

Returns:

a comparator representing the opposite order of c.

comparingFloat

public static <T> Comparator<T> comparingFloat(com.github.tommyettinger.function.ObjToFloatFunction<? super T> keyExtractor)

Accepts a function that extracts a float sort key from a type T, and returns a Comparator<T> that compares by that sort key.
This is in ObjectComparators and not in FloatComparators because there are similar methods in Comparator, such as Comparator.comparingDouble(ToDoubleFunction).
The returned comparator is not serializable, by design. This library intentionally avoids the java.io.Serializable ecosystem because of the serious security issues it near-constantly accrues.

Type Parameters:

T - the type of element to be compared

Parameters:

keyExtractor - the function used to extract the float sort key

Returns:

a comparator that compares by an extracted key

Throws:

NullPointerException - if the argument is null

sort

public static <K> void sort(List<K> items,
 Comparator<? super K> c)

Sorts all of items by simply calling sort(List, int, int, Comparator) setting from and to so the whole array is sorted.

Parameters:

items - the List to be sorted

c - a Comparator to alter the sort order; if null, the natural order will be used

sort

public static <K> void sort(List<K> items,
 int from,
 int to,
 Comparator<? super K> c)

Sorts the specified range of elements 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.

Parameters:

items - the List to be sorted

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

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

c - a Comparator to alter the sort order; if null, the natural order will be used

sort

public static <K> void sort(K[] items,
 Comparator<? super K> c)

Sorts all of items by simply calling sort(List, int, int, Comparator) setting from and to so the whole array is sorted.

Parameters:

items - the List to be sorted

c - a Comparator to alter the sort order; if null, the natural order will be used

sort

public static <K> void sort(K[] items,
 int from,
 int to,
 Comparator<? super K> c)

Sorts the specified range of elements 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.

Parameters:

items - the List to be sorted

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

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

c - a Comparator to alter the sort order; if null, the natural order will be used