Module dk.cloudcreate.essentials.shared

Package dk.cloudcreate.essentials.shared.collections

Class Lists

java.lang.Object

dk.cloudcreate.essentials.shared.collections.Lists

public final class Lists
extends Object

List utility methods

Constructor Summary

Constructors

Constructor	Description
Lists()

Method Summary

Modifier and Type	Method	Description
static <T> Optional<T>	first(List<T> list)	Get the first element in a list
static <T> Optional<T>	last(List<T> list)	Get the last element in a list
static <T> List<T>	nullSafeList(List<T> list)
static <T> Stream<Pair<Integer,T>>	toIndexedStream(List<T> list)	Convert the list to an 0-based Indexed Stream consisting of Pair's, where each Pair consists of the 0-based Index (i.e. the first index has value 0) and the corresponding List element at the given index: Pair<Index, List-element-at-the-given-index> Example: List.of("A", "B", "C") will return a Stream of: Pair(0, "A") Pair(1, "B") Pair(2, "C")

Methods inherited from class java.lang.Object

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

Constructor Details

Lists

public Lists()

Method Details

toIndexedStream

public static <T> Stream<Pair<Integer,T>> toIndexedStream(List<T> list)

Convert the list to an 0-based Indexed Stream consisting of Pair's, where each Pair consists of the 0-based Index (i.e. the first index has value 0) and the corresponding List element at the given index: Pair<Index, List-element-at-the-given-index>

Example:
List.of("A", "B", "C") will return a Stream of:

• Pair(0, "A")
• Pair(1, "B")
• Pair(2, "C")

Type Parameters:

T - the type of list element

Parameters:

list - the list that's converted to an indexed stream

Returns:

the indexed list

first

public static <T> Optional<T> first(List<T> list)

Get the first element in a list

Type Parameters:

T - the type of elements in the list

Parameters:

list - the non-null list

Returns:

the first element wrapped in an Optional or Optional.empty() if the list is empty

last

public static <T> Optional<T> last(List<T> list)

Get the last element in a list

Type Parameters:

T - the type of elements in the list

Parameters:

list - the non-null list

Returns:

the last element wrapped in an Optional or Optional.empty() if the list is empty

nullSafeList

public static <T> List<T> nullSafeList(List<T> list)