org.danilopianini.lang

Class CollectionUtils

java.lang.Object

org.danilopianini.lang.CollectionUtils

public final class CollectionUtils
extends Object

Constructor Summary

Constructors

Modifier	Constructor and Description
private	CollectionUtils()

Method Summary

Modifier and Type	Method and Description
static <E> void	forEach(List<E> s, BiConsumer<? super Integer,? super E> f) Facility for executing lambdas requiring access to the index.
static <E,R> List<R>	map(List<E> s, BiFunction<? super Integer,? super E,? extends R> f) Facility for executing lambdas requiring access to the index.
static int	optimalSizeMap(Collection<?> c) Computes the size of a map (with 0.75 as load factor) such as the map does not need to resize itself if all the elements of c are passed.
static int	optimalSizeMap(int n) Computes the size of a map (with 0.75 as load factor) such as the map does not need to resize itself if n elements are added.

Methods inherited from class java.lang.Object

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

Constructor Detail

CollectionUtils

private CollectionUtils()

Method Detail

optimalSizeMap

public static int optimalSizeMap(int n)

Computes the size of a map (with 0.75 as load factor) such as the map does not need to resize itself if n elements are added.

Parameters:

n - the number of elements

Returns:

the size of the map

optimalSizeMap

public static int optimalSizeMap(Collection<?> c)

Computes the size of a map (with 0.75 as load factor) such as the map does not need to resize itself if all the elements of c are passed.

Parameters:

c - the collection containing the elements

Returns:

the size of the map

forEach

public static <E> void forEach(List<E> s,
                               BiConsumer<? super Integer,? super E> f)

Facility for executing lambdas requiring access to the index. The passed function will run once per element of the list. Avoid side effects on the list, they won't work correctly.

Type Parameters:

E - List data type

Parameters:

s - the List to apply the lambda on

f - the BiConsumer to apply to each element

map

public static <E,R> List<R> map(List<E> s,
                                BiFunction<? super Integer,? super E,? extends R> f)

Facility for executing lambdas requiring access to the index. The passed function will run once per element of the list and its result will be added in the corresponding position of the returned List. Avoid side effects on the list, they won't work correctly.

Type Parameters:

E - input List data type

R - return List data type

Parameters:

s - the List to apply the lambda on

f - the BiFunction to apply to each element

Returns:

a new list containing all the element produced by the BiFunction applied to the give List