fj.data

Class NonEmptyList<A>

java.lang.Object

fj.data.NonEmptyList<A>

All Implemented Interfaces:

java.lang.Iterable<A>

public final class NonEmptyList<A>
extends java.lang.Object
implements java.lang.Iterable<A>

Provides an in-memory, immutable, singly linked list with total head and tail.

Field Summary

Fields

Modifier and Type	Field and Description
A	head The first element of this linked list.
List<A>	tail This list without the first element.

Method Summary

Modifier and Type	Method and Description
NonEmptyList<A>	append(NonEmptyList<A> as) Appends the given list to this list.
<B> NonEmptyList<B>	bind(F<A,NonEmptyList<B>> f) Binds the given function across each element of this list with a final join.
NonEmptyList<A>	cons(A a) Prepend the given value to this list.
static <A> Option<NonEmptyList<A>>	fromList(List<A> as) Returns a potential non-empty list from the given list.
java.util.Iterator<A>	iterator() Returns an iterator for this non-empty list.
<B> NonEmptyList<B>	map(F<A,B> f) Maps the given function across this list.
<B> NonEmptyList<B>	mapTails(F<NonEmptyList<A>,B> f) Maps the given function across the tails of this list (comonad pattern).
static <A> F<A,NonEmptyList<A>>	nel() Returns a function that puts an element into a non-empty list.
static <A> NonEmptyList<A>	nel(A head) Return a non-empty list with the given value.
static <A> NonEmptyList<A>	nel(A head, List<A> tail) Return a non-empty list with the given head and tail.
NonEmptyList<NonEmptyList<A>>	sublists() Returns a NonEmptyList of the sublists of this list.
NonEmptyList<NonEmptyList<A>>	tails() Returns a NonEmptyList of the tails of this list.
java.util.Collection<A>	toCollection() Projects an immutable collection of this non-empty list.
static <A> F<NonEmptyList<A>,List<A>>	toList_() Returns a function that takes a non-empty list to a list.
List<A>	toList() Returns a List projection of this list.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

head

public final A head

The first element of this linked list.

tail

public final List<A> tail

This list without the first element.

Method Detail

iterator

public java.util.Iterator<A> iterator()

Returns an iterator for this non-empty list. This method exists to permit the use in a for-each loop.

Specified by:

iterator in interface java.lang.Iterable<A>

Returns:

A iterator for this non-empty list.

cons

public NonEmptyList<A> cons(A a)

Prepend the given value to this list.

Parameters:

a - The value to prepend.

Returns:

A non-empty list with an extra element.

append

public NonEmptyList<A> append(NonEmptyList<A> as)

Appends the given list to this list.

Parameters:

as - The list to append.

Returns:

A new list with the given list appended.

map

public <B> NonEmptyList<B> map(F<A,B> f)

Maps the given function across this list.

Parameters:

f - The function to map across this list.

Returns:

A new list after the given function has been applied to each element.

bind

public <B> NonEmptyList<B> bind(F<A,NonEmptyList<B>> f)

Binds the given function across each element of this list with a final join.

Parameters:

f - The function to apply to each element of this list.

Returns:

A new list after performing the map, then final join.

sublists

public NonEmptyList<NonEmptyList<A>> sublists()

Returns a NonEmptyList of the sublists of this list.

Returns:

a NonEmptyList of the sublists of this list.

tails

public NonEmptyList<NonEmptyList<A>> tails()

Returns a NonEmptyList of the tails of this list. A list is considered a tail of itself for the purpose of this function (Comonad pattern).

Returns:

A NonEmptyList of the tails of this list.

mapTails

public <B> NonEmptyList<B> mapTails(F<NonEmptyList<A>,B> f)

Maps the given function across the tails of this list (comonad pattern).

Parameters:

f - The function to map across the tails of this list.

Returns:

The results of applying the given function to the tails of this list, as a NonEmptyList.

toList

public List<A> toList()

Returns a List projection of this list.

Returns:

A List projection of this list.

toCollection

public java.util.Collection<A> toCollection()

Projects an immutable collection of this non-empty list.

Returns:

An immutable collection of this non-empty list.

toList_

public static <A> F<NonEmptyList<A>,List<A>> toList_()

Returns a function that takes a non-empty list to a list.

Returns:

A function that takes a non-empty list to a list.

nel

public static <A> NonEmptyList<A> nel(A head,
                                      List<A> tail)

Return a non-empty list with the given head and tail.

Parameters:

head - The first element of the new list.

tail - The remaining elements of the new list.

Returns:

A non-empty list with the given head and tail.

nel

public static <A> NonEmptyList<A> nel(A head)

Return a non-empty list with the given value.

Parameters:

head - The value in the non-empty list.

Returns:

A non-empty list with the given value.

nel

public static <A> F<A,NonEmptyList<A>> nel()

Returns a function that puts an element into a non-empty list.

Returns:

A function that puts an element into a non-empty list.

fromList

public static <A> Option<NonEmptyList<A>> fromList(List<A> as)

Returns a potential non-empty list from the given list. A non-value is returned if the given list is empty.

Parameters:

as - The list to construct a potential non-empty list with.

Returns:

A potential non-empty list from the given list.