no.motif.types

Interface Elements<T>

Type Parameters:

T - The type of the contained objects.

All Superinterfaces:

Appendable<T>, Existance<T>, Filterable<T>, HeadAndTail<T>, Iterable<T>, Mappable<T>, Prependable<T>, Reducible<T>, Repeatable<T>, SideEffectable<T>, YieldsJavaCollection<T>

All Known Implementing Classes:

PreparedIterable

public interface Elements<T>
extends Mappable<T>, Filterable<T>, Appendable<T>, Prependable<T>, SideEffectable<T>, Repeatable<T>, HeadAndTail<T>, YieldsJavaCollection<T>, Existance<T>, Iterable<T>, Reducible<T>

This is the main type of Motif's collection API and encompasses all the operations available to manipulate and query the the contained elements, as well as converting back to Java Collection Framework collections.

Method Summary

Modifier and Type	Method and Description
Elements<T>	eval() Force-evaluate the current elements, applying all composed functions on each element.
Elements<T>	filter(Predicate<? super T> filter) Provide a predicate that evaluates which element(s) to be included.
<O> Elements<O>	flatMap(Fn<? super T,? extends Iterable<O>> fn)
Optional<T>	head() Gets the head, or first element, if it exists.
Elements<Elem<T>>	indexed() Couple each element with its positional index.
Elements<Elem<T>>	indexedFrom(int startIndex) Couple each element with its positional index, starting from a given index.
String	join() Join all elements to one String.
String	join(String separator) Join all elements to one String with all elements joined with the given separator.
Optional<T>	last() Gets the last element.
<O> Elements<O>	map(Fn<? super T,O> function) Apply a function on any contained element(s), returning the result in a new mappable container.
Elements<T>	repeat(int times) Repeat the contained elements a given amount of times.
Elements<T>	tail() Gets the tail, i.e. the remainder after the head.
Elements<T>	take(int amount) Take only a maximum amount of elements.
Elements<T>	takeUntil(Predicate<? super T> predicate) Take elements until a given predicate evaluates to true.
Elements<T>	takeWhile(Predicate<? super T> predicate) Take elements as long as a given predicate evaluates to true.

Methods inherited from interface no.motif.types.Appendable

append, append

Methods inherited from interface no.motif.types.Prependable

prepend, prepend

Methods inherited from interface java.lang.Iterable

forEach, iterator, spliterator

Methods inherited from interface no.motif.types.SideEffectable

each

Methods inherited from interface no.motif.types.YieldsJavaCollection

collect, collectIn, groupBy, mapBy, sorted, sortedBy

Methods inherited from interface no.motif.types.Existance

exists, isEmpty

Methods inherited from interface no.motif.types.Reducible

reduce

Method Detail

indexed

Elements<Elem<T>> indexed()

Couple each element with its positional index.

Returns:

The elements wrapped in Elems.

indexedFrom

Elements<Elem<T>> indexedFrom(int startIndex)

Couple each element with its positional index, starting from a given index.

Parameters:

startIndex - the beginning index to assign to the first element.

Returns:

The elements wrapped in Elems.

take

Elements<T> take(int amount)

Take only a maximum amount of elements.

Parameters:

amount - the amount to take.

Returns:

the elements

takeWhile

Elements<T> takeWhile(Predicate<? super T> predicate)

Take elements as long as a given predicate evaluates to true.

Parameters:

predicate - The predicate, when evaluates an element to false, will not include that element, nor any more elements.

Returns:

the elements

takeUntil

Elements<T> takeUntil(Predicate<? super T> predicate)

Take elements until a given predicate evaluates to true.

Parameters:

predicate - The predicate, when evaluates an element to true, will not include that element, nor any more elements.

Returns:

the elements

last

Optional<T> last()

Gets the last element.

head

Optional<T> head()

Description copied from interface: HeadAndTail

Gets the head, or first element, if it exists.

Specified by:

head in interface HeadAndTail<T>

tail

Elements<T> tail()

Description copied from interface: HeadAndTail

Gets the tail, i.e. the remainder after the head.

Specified by:

tail in interface HeadAndTail<T>

Returns:

The tail, which may be empty if there is only a head element.

join

String join()

Join all elements to one String.

Returns:

the joined string

join

String join(String separator)

Join all elements to one String with all elements joined with the given separator.

Returns:

the joined string

map

<O> Elements<O> map(Fn<? super T,O> function)

Description copied from interface: Mappable

Apply a function on any contained element(s), returning the result in a new mappable container.

Specified by:

map in interface Mappable<T>

Parameters:

function - The function to apply.

Returns:

The result from the function application.

filter

Elements<T> filter(Predicate<? super T> filter)

Description copied from interface: Filterable

Provide a predicate that evaluates which element(s) to be included.

Specified by:

filter in interface Filterable<T>

Parameters:

filter - The predicate, when evaluates an element to false, will exclude that element.

Returns:

the filtered elements.

repeat

Elements<T> repeat(int times)

Description copied from interface: Repeatable

Repeat the contained elements a given amount of times.

• [].repeat(x) == []
• Xs.repeat(0) == []
• Xs.repeat(1) == Xs
• [x, y].repeat(3) == [x, y, x, y, x, y]
• [x, y].repeat(-1) throws IllegalArgumentException (eventually)

Specified by:

repeat in interface Repeatable<T>

Parameters:

times - The amount to repeat.

Returns:

The elements, repeated the given amount of times.

flatMap

<O> Elements<O> flatMap(Fn<? super T,? extends Iterable<O>> fn)

eval

Elements<T> eval()

Force-evaluate the current elements, applying all composed functions on each element. This is useful when needing to iterate elements several times, especially if the composed functions are expensive to evaluate and/or not referentially transparent. This is an escape-hatch from the lazy design of Elements.

Returns:

same type of elements, with all elements evaluated.