T
- component type of this Streampublic abstract class Stream<T> extends java.lang.Object implements LinearSeq<T>
Stream
is lazy sequence of elements which may be infinitely long.
Its immutability makes it suitable for concurrent programming.
A Stream
is composed of a head
element and a lazy evaluated tail
Stream
.
There are two implementations of the Stream
interface:
Stream.Empty
, which represents the empty Stream
.Stream.Cons
, which represents a Stream
containing one or more elements.Stream
:
// factory methods
Stream.empty() // = Stream.of() = Nil.instance()
Stream.of(x) // = new Cons<>(x, Nil.instance())
Stream.of(Object...) // e.g. Stream.of(1, 2, 3)
Stream.ofAll(Iterable) // e.g. Stream.ofAll(List.of(1, 2, 3)) = 1, 2, 3
Stream.ofAll(<primitive array>) // e.g. List.ofAll(1, 2, 3) = 1, 2, 3
// int sequences
Stream.from(0) // = 0, 1, 2, 3, ...
Stream.range(0, 3) // = 0, 1, 2
Stream.rangeClosed(0, 3) // = 0, 1, 2, 3
// generators
Stream.cons(Object, Supplier) // e.g. Stream.cons(current, () -> next(current));
Stream.continually(Supplier) // e.g. Stream.continually(Math::random);
Stream.iterate(Object, Function)// e.g. Stream.iterate(1, i -> i * 2);
Factory method applications:
Stream<Integer> s1 = Stream.of(1);
Stream<Integer> s2 = Stream.of(1, 2, 3);
// = Stream.of(new Integer[] {1, 2, 3});
Stream<int[]> s3 = Stream.ofAll(1, 2, 3);
Stream<List<Integer>> s4 = Stream.ofAll(List.of(1, 2, 3));
Stream<Integer> s5 = Stream.ofAll(1, 2, 3);
Stream<Integer> s6 = Stream.ofAll(List.of(1, 2, 3));
// cuckoo's egg
Stream<Integer[]> s7 = Stream.<Integer[]> of(new Integer[] {1, 2, 3});
Example: Generating prime numbers
// = Stream(2L, 3L, 5L, 7L, ...)
Stream.iterate(2L, PrimeNumbers::nextPrimeFrom)
// helpers
static long nextPrimeFrom(long num) {
return Stream.from(num + 1).find(PrimeNumbers::isPrime).get();
}
static boolean isPrime(long num) {
return !Stream.rangeClosed(2L, (long) Math.sqrt(num)).exists(d -> num % d == 0);
}
See Okasaki, Chris: Purely Functional Data Structures (p. 34 ff.). Cambridge, 2003.Modifier and Type | Class and Description |
---|---|
static class |
Stream.Cons<T>
Deprecated.
will be removed from the public API
|
static class |
Stream.Empty<T>
Deprecated.
will be removed from the public API
|
Modifier and Type | Method and Description |
---|---|
abstract Stream<T> |
append(T element)
Appends an element to this.
|
abstract Stream<T> |
appendAll(java.lang.Iterable<? extends T> elements)
Appends all given elements to this.
|
Stream<T> |
appendSelf(java.util.function.Function<? super Stream<T>,? extends Stream<T>> mapper)
Appends itself to the end of stream with
mapper function. |
T |
apply(java.lang.Integer index)
A
Seq is a partial function which returns the element at the specified index if the
index is valid. |
java.util.List<T> |
asJava()
Creates an immutable
List view on top of this Seq ,
i.e. |
Stream<T> |
asJava(java.util.function.Consumer<? super java.util.List<T>> action)
Creates an immutable
List view on top of this Seq
that is passed to the given action . |
java.util.List<T> |
asJavaMutable()
Creates a mutable
List view on top of this Seq ,
i.e. |
Stream<T> |
asJavaMutable(java.util.function.Consumer<? super java.util.List<T>> action)
Creates a mutable
List view on top of this Seq
that is passed to the given action . |
<R> Stream<R> |
collect(PartialFunction<? super T,? extends R> partialFunction)
Collects all elements that are in the domain of the given
partialFunction by mapping the elements to type R . |
static <T> java.util.stream.Collector<T,java.util.ArrayList<T>,Stream<T>> |
collector()
Returns a
Collector which may be used in conjunction with
Stream.collect(java.util.stream.Collector) to obtain a Stream . |
Stream<Stream<T>> |
combinations()
Returns the union of all combinations from k = 0 to length().
|
Stream<Stream<T>> |
combinations(int k)
Returns the k-combination of this traversable, i.e.
|
static <T> Stream<T> |
concat(java.lang.Iterable<? extends java.lang.Iterable<? extends T>> iterables)
Lazily creates a Stream in O(1) which traverses along the concatenation of the given iterables.
|
static <T> Stream<T> |
concat(java.lang.Iterable<? extends T>... iterables)
Lazily creates a Stream in O(1) which traverses along the concatenation of the given iterables.
|
static <T> Stream<T> |
cons(T head,
java.util.function.Supplier<? extends Stream<? extends T>> tailSupplier)
Constructs a Stream of a head element and a tail supplier.
|
static <T> Stream<T> |
continually(java.util.function.Supplier<? extends T> supplier)
Generates an (theoretically) infinitely long Stream using a value Supplier.
|
static <T> Stream<T> |
continually(T t)
Repeats an element infinitely often.
|
Iterator<Stream<T>> |
crossProduct(int power)
Calculates the n-ary cartesian power (or cross product or simply product) of this.
|
Stream<T> |
cycle()
Repeat the elements of this Stream infinitely.
|
Stream<T> |
cycle(int count)
Repeat the elements of this Stream
count times. |
Stream<T> |
distinct()
Returns a new version of this which contains no duplicates.
|
Stream<T> |
distinctBy(java.util.Comparator<? super T> comparator)
Returns a new version of this which contains no duplicates.
|
<U> Stream<T> |
distinctBy(java.util.function.Function<? super T,? extends U> keyExtractor)
Returns a new version of this which contains no duplicates.
|
Stream<T> |
drop(int n)
Drops the first n elements of this or all elements, if this length < n.
|
Stream<T> |
dropRight(int n)
Drops the last n elements of this or all elements, if this length < n.
|
Stream<T> |
dropRightUntil(java.util.function.Predicate<? super T> predicate)
Drops elements until the predicate holds for the current element, starting from the end.
|
Stream<T> |
dropRightWhile(java.util.function.Predicate<? super T> predicate)
Drops elements while the predicate holds for the current element, starting from the end.
|
Stream<T> |
dropUntil(java.util.function.Predicate<? super T> predicate)
Drops elements until the predicate holds for the current element.
|
Stream<T> |
dropWhile(java.util.function.Predicate<? super T> predicate)
Drops elements while the predicate holds for the current element.
|
static <T> Stream<T> |
empty()
Returns the single instance of Nil.
|
Stream<T> |
extend(java.util.function.Function<? super T,? extends T> nextFunction)
Extends (continues) this
Stream with a Stream of values created by applying
consecutively provided Function to the last element of the original Stream. |
Stream<T> |
extend(java.util.function.Supplier<? extends T> nextSupplier)
Extends (continues) this
Stream with values provided by a Supplier |
Stream<T> |
extend(T next)
Extends (continues) this
Stream with a constantly repeated value. |
static <T> Stream<T> |
fill(int n,
java.util.function.Supplier<? extends T> s)
Returns a Stream containing
n values supplied by a given Supplier s . |
static <T> Stream<T> |
fill(int n,
T element)
Returns a Stream containing
n times the given element |
Stream<T> |
filter(java.util.function.Predicate<? super T> predicate)
Returns a new traversable consisting of all elements which satisfy the given predicate.
|
Stream<T> |
filterNot(java.util.function.Predicate<? super T> predicate)
Returns a new traversable consisting of all elements which do not satisfy the given predicate.
|
<U> Stream<U> |
flatMap(java.util.function.Function<? super T,? extends java.lang.Iterable<? extends U>> mapper)
FlatMaps this Traversable.
|
static Stream<java.lang.Integer> |
from(int value)
Returns an infinitely long Stream of
int values starting from from . |
static Stream<java.lang.Integer> |
from(int value,
int step)
Returns an infinite long Stream of
int values starting from value and spaced by step . |
static Stream<java.lang.Long> |
from(long value)
Returns an infinitely long Stream of
long values starting from from . |
static Stream<java.lang.Long> |
from(long value,
long step)
Returns an infinite long Stream of
long values starting from value and spaced by step . |
T |
get(int index)
Returns the element at the specified index.
|
Option<T> |
getOption(int index)
Returns an optional value, which may element at the specified index, or be empty
if the index is invalid for this collection.
|
T |
getOrElse(int index,
T defaultValue)
Returns the element at the specified index, or the default value you give if
the index is invalid for this collection.
|
<C> Map<C,Stream<T>> |
groupBy(java.util.function.Function<? super T,? extends C> classifier)
Groups this elements by classifying the elements.
|
Iterator<Stream<T>> |
grouped(int size)
Groups this
Traversable into fixed size blocks. |
boolean |
hasDefiniteSize()
Checks if this Traversable is known to have a finite size.
|
int |
indexOf(T element,
int from)
Returns the index of the first occurrence of the given element after or at some start index
or -1 if this does not contain the given element.
|
Stream<T> |
init()
Dual of Traversable.tail(), returning all elements except the last.
|
Option<Stream<T>> |
initOption()
Dual of Traversable.tailOption(), returning all elements except the last as
Option . |
Stream<T> |
insert(int index,
T element)
Inserts the given element at the specified index.
|
Stream<T> |
insertAll(int index,
java.lang.Iterable<? extends T> elements)
Inserts the given elements at the specified index.
|
Stream<T> |
intersperse(T element)
Inserts an element between all elements of this Traversable.
|
boolean |
isAsync()
A
Stream is computed synchronously. |
boolean |
isDefinedAt(java.lang.Integer index)
Deprecated.
|
boolean |
isLazy()
A
Stream is computed lazily. |
boolean |
isTraversableAgain()
Checks if this Traversable can be repeatedly traversed.
|
static <T> Stream<T> |
iterate(java.util.function.Supplier<? extends Option<? extends T>> supplier)
Generates a (theoretically) infinitely long Stream using a repeatedly invoked supplier
that provides a
Some for each next value and a None for the end. |
static <T> Stream<T> |
iterate(T seed,
java.util.function.Function<? super T,? extends T> f)
Generates a (theoretically) infinitely long Stream using a function to calculate the next value
based on the previous.
|
T |
last()
Dual of Traversable.head(), returning the last element.
|
int |
lastIndexOf(T element,
int end)
Returns the index of the last occurrence of the given element before or at a given end index
or -1 if this does not contain the given element.
|
Stream<T> |
leftPadTo(int length,
T element)
A copy of this sequence with an element prepended until a given target length is reached.
|
int |
length()
Computes the number of elements of this Traversable.
|
<U> Stream<U> |
map(java.util.function.Function<? super T,? extends U> mapper)
Maps the elements of this
Traversable to elements of a new type preserving their order, if any. |
static <T> Stream<T> |
narrow(Stream<? extends T> stream)
Narrows a widened
Stream<? extends T> to Stream<T>
by performing a type-safe cast. |
static <T> Stream<T> |
of(T... elements)
Creates a Stream of the given elements.
|
static <T> Stream<T> |
of(T element)
Returns a singleton
Stream , i.e. |
static Stream<java.lang.Boolean> |
ofAll(boolean... elements)
Creates a Stream from boolean values.
|
static Stream<java.lang.Byte> |
ofAll(byte... elements)
Creates a Stream from byte values.
|
static Stream<java.lang.Character> |
ofAll(char... elements)
Creates a Stream from char values.
|
static Stream<java.lang.Double> |
ofAll(double... elements)
Creates a Stream values double values.
|
static Stream<java.lang.Float> |
ofAll(float... elements)
Creates a Stream from float values.
|
static Stream<java.lang.Integer> |
ofAll(int... elements)
Creates a Stream from int values.
|
static <T> Stream<T> |
ofAll(java.lang.Iterable<? extends T> elements)
Creates a Stream of the given elements.
|
static Stream<java.lang.Long> |
ofAll(long... elements)
Creates a Stream from long values.
|
static Stream<java.lang.Short> |
ofAll(short... elements)
Creates a Stream from short values.
|
static <T> Stream<T> |
ofAll(java.util.stream.Stream<? extends T> javaStream)
Creates a Stream that contains the elements of the given
Stream . |
Stream<T> |
orElse(java.lang.Iterable<? extends T> other)
Returns this
Traversable if it is nonempty, otherwise return the alternative. |
Stream<T> |
orElse(java.util.function.Supplier<? extends java.lang.Iterable<? extends T>> supplier)
Returns this
Traversable if it is nonempty, otherwise return the result of evaluating supplier. |
Stream<T> |
padTo(int length,
T element)
A copy of this sequence with an element appended until a given target length is reached.
|
Tuple2<Stream<T>,Stream<T>> |
partition(java.util.function.Predicate<? super T> predicate)
Creates a partition of this
Traversable by splitting this elements in two in distinct traversables
according to a predicate. |
Stream<T> |
patch(int from,
java.lang.Iterable<? extends T> that,
int replaced)
Produces a new list where a slice of elements in this list is replaced by another sequence.
|
Stream<T> |
peek(java.util.function.Consumer<? super T> action)
Performs the given
action on the first element if this is an eager implementation. |
Stream<Stream<T>> |
permutations()
Computes all unique permutations.
|
Stream<T> |
prepend(T element)
Prepends an element to this.
|
Stream<T> |
prependAll(java.lang.Iterable<? extends T> elements)
Prepends all given elements to this.
|
static Stream<java.lang.Character> |
range(char from,
char toExclusive) |
static Stream<java.lang.Integer> |
range(int from,
int toExclusive)
Creates a Stream of int numbers starting from
from , extending to toExclusive - 1 . |
static Stream<java.lang.Long> |
range(long from,
long toExclusive)
Creates a Stream of long numbers starting from
from , extending to toExclusive - 1 . |
static Stream<java.lang.Character> |
rangeBy(char from,
char toExclusive,
int step) |
static Stream<java.lang.Double> |
rangeBy(double from,
double toExclusive,
double step) |
static Stream<java.lang.Integer> |
rangeBy(int from,
int toExclusive,
int step)
Creates a Stream of int numbers starting from
from , extending to toExclusive - 1 ,
with step . |
static Stream<java.lang.Long> |
rangeBy(long from,
long toExclusive,
long step)
Creates a Stream of long numbers starting from
from , extending to toExclusive - 1 ,
with step . |
static Stream<java.lang.Character> |
rangeClosed(char from,
char toInclusive) |
static Stream<java.lang.Integer> |
rangeClosed(int from,
int toInclusive)
Creates a Stream of int numbers starting from
from , extending to toInclusive . |
static Stream<java.lang.Long> |
rangeClosed(long from,
long toInclusive)
Creates a Stream of long numbers starting from
from , extending to toInclusive . |
static Stream<java.lang.Character> |
rangeClosedBy(char from,
char toInclusive,
int step) |
static Stream<java.lang.Double> |
rangeClosedBy(double from,
double toInclusive,
double step) |
static Stream<java.lang.Integer> |
rangeClosedBy(int from,
int toInclusive,
int step)
Creates a Stream of int numbers starting from
from , extending to toInclusive ,
with step . |
static Stream<java.lang.Long> |
rangeClosedBy(long from,
long toInclusive,
long step)
Creates a Stream of long numbers starting from
from , extending to toInclusive ,
with step . |
Stream<T> |
remove(T element)
Removes the first occurrence of the given element.
|
Stream<T> |
removeAll(java.lang.Iterable<? extends T> elements)
Removes all occurrences of the given elements.
|
Stream<T> |
removeAll(T element)
Removes all occurrences of the given element.
|
Stream<T> |
removeAt(int index)
Removes the element at the specified position in this sequence.
|
Stream<T> |
removeFirst(java.util.function.Predicate<T> predicate)
Removes the first occurrence that satisfy predicate
|
Stream<T> |
removeLast(java.util.function.Predicate<T> predicate)
Removes the last occurrence that satisfy predicate
|
Stream<T> |
replace(T currentElement,
T newElement)
Replaces the first occurrence (if exists) of the given currentElement with newElement.
|
Stream<T> |
replaceAll(T currentElement,
T newElement)
Replaces all occurrences of the given currentElement with newElement.
|
Stream<T> |
retainAll(java.lang.Iterable<? extends T> elements)
Keeps all occurrences of the given elements from this.
|
Stream<T> |
reverse()
Reverses the order of elements.
|
Stream<T> |
rotateLeft(int n)
Circular rotates the elements by the specified distance to the left direction.
|
Stream<T> |
rotateRight(int n)
Circular rotates the elements by the specified distance to the right direction.
|
Stream<T> |
scan(T zero,
java.util.function.BiFunction<? super T,? super T,? extends T> operation)
Computes a prefix scan of the elements of the collection.
|
<U> Stream<U> |
scanLeft(U zero,
java.util.function.BiFunction<? super U,? super T,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going left to right.
|
<U> Stream<U> |
scanRight(U zero,
java.util.function.BiFunction<? super T,? super U,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going right to left.
|
Stream<T> |
shuffle()
Randomize the order of the elements in the current sequence.
|
Stream<T> |
shuffle(java.util.Random random)
Randomize the order of the elements in the current sequence using the given source
of randomness.
|
Stream<T> |
slice(int beginIndex,
int endIndex)
Returns a Seq that is a slice of this.
|
Iterator<Stream<T>> |
slideBy(java.util.function.Function<? super T,?> classifier)
Slides a non-overlapping window of a variable size over this
Traversable . |
Iterator<Stream<T>> |
sliding(int size)
Slides a window of a specific
size and step size 1 over this Traversable by calling
Traversable.sliding(int, int) . |
Iterator<Stream<T>> |
sliding(int size,
int step)
Slides a window of a specific
size and step size over this Traversable . |
<U> Stream<T> |
sortBy(java.util.Comparator<? super U> comparator,
java.util.function.Function<? super T,? extends U> mapper)
Sorts this elements by comparing the elements in a different domain, using the given
mapper . |
<U extends java.lang.Comparable<? super U>> |
sortBy(java.util.function.Function<? super T,? extends U> mapper)
Sorts this elements by comparing the elements in a different domain, using the given
mapper . |
Stream<T> |
sorted()
Sorts this elements according to their natural order.
|
Stream<T> |
sorted(java.util.Comparator<? super T> comparator)
Sorts this elements according to the provided
Comparator . |
Tuple2<Stream<T>,Stream<T>> |
span(java.util.function.Predicate<? super T> predicate)
Returns a tuple where the first element is the longest prefix of elements that satisfy the given
predicate and the second element is the remainder. |
Tuple2<Stream<T>,Stream<T>> |
splitAt(int n)
Splits a Seq at the specified index.
|
Tuple2<Stream<T>,Stream<T>> |
splitAt(java.util.function.Predicate<? super T> predicate)
Splits a sequence at the first element which satisfies the
Predicate , e.g. |
Tuple2<Stream<T>,Stream<T>> |
splitAtInclusive(java.util.function.Predicate<? super T> predicate)
Splits a sequence at the first element which satisfies the
Predicate , e.g. |
java.lang.String |
stringPrefix()
Returns the name of this Value type, which is used by toString().
|
Stream<T> |
subSequence(int beginIndex)
Returns a Seq that is a subsequence of this.
|
Stream<T> |
subSequence(int beginIndex,
int endIndex)
Returns a Seq that is a subsequence of this.
|
static <T> Stream<T> |
tabulate(int n,
java.util.function.Function<? super java.lang.Integer,? extends T> f)
Returns a Stream containing
n values of a given Function f
over a range of integer values from 0 to n - 1 . |
abstract Stream<T> |
tail()
Drops the first element of a non-empty Traversable.
|
Option<Stream<T>> |
tailOption()
Drops the first element of a non-empty Traversable and returns an
Option . |
Stream<T> |
take(int n)
Takes the first n elements of this or all elements, if this length < n.
|
Stream<T> |
takeRight(int n)
Takes the last n elements of this or all elements, if this length < n.
|
Stream<T> |
takeRightUntil(java.util.function.Predicate<? super T> predicate)
Takes elements until the predicate holds for the current element, starting from the end.
|
Stream<T> |
takeRightWhile(java.util.function.Predicate<? super T> predicate)
Takes elements while the predicate holds for the current element, starting from the end.
|
Stream<T> |
takeUntil(java.util.function.Predicate<? super T> predicate)
Takes elements until the predicate holds for the current element.
|
Stream<T> |
takeWhile(java.util.function.Predicate<? super T> predicate)
Takes elements while the predicate holds for the current element.
|
<U> U |
transform(java.util.function.Function<? super Stream<T>,? extends U> f)
Transforms this
Stream . |
static <T> Stream<Stream<T>> |
transpose(Stream<Stream<T>> matrix)
Transposes the rows and columns of a
Stream matrix. |
static <T> Stream<T> |
unfold(T seed,
java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends T>>> f)
Creates a Stream from a seed value and a function.
|
static <T,U> Stream<U> |
unfoldLeft(T seed,
java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends U>>> f)
Creates a Stream from a seed value and a function.
|
static <T,U> Stream<U> |
unfoldRight(T seed,
java.util.function.Function<? super T,Option<Tuple2<? extends U,? extends T>>> f)
Creates a Stream from a seed value and a function.
|
Stream<T> |
update(int index,
java.util.function.Function<? super T,? extends T> updater)
Updates the given element at the specified index using the specified function.
|
Stream<T> |
update(int index,
T element)
Updates the given element at the specified index.
|
<U> Stream<Tuple2<T,U>> |
zip(java.lang.Iterable<? extends U> that)
Returns a traversable formed from this traversable and another Iterable collection by combining
corresponding elements in pairs.
|
<U> Stream<Tuple2<T,U>> |
zipAll(java.lang.Iterable<? extends U> iterable,
T thisElem,
U thatElem)
Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in
pairs.
|
<U,R> Stream<R> |
zipWith(java.lang.Iterable<? extends U> that,
java.util.function.BiFunction<? super T,? super U,? extends R> mapper)
Returns a traversable formed from this traversable and another Iterable collection by mapping elements.
|
Stream<Tuple2<T,java.lang.Integer>> |
zipWithIndex()
Zips this traversable with its indices.
|
<U> Stream<U> |
zipWithIndex(java.util.function.BiFunction<? super T,? super java.lang.Integer,? extends U> mapper)
Returns a traversable formed from this traversable and another Iterable collection by mapping elements.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
asPartialFunction, indexOfSlice, indexWhere, lastIndexOfSlice, lastIndexWhere, narrow, reverseIterator, search, search, segmentLength
containsSlice, crossProduct, crossProduct, endsWith, foldRight, indexOf, indexOfOption, indexOfOption, indexOfSlice, indexOfSliceOption, indexOfSliceOption, indexWhere, indexWhereOption, indexWhereOption, isSequential, iterator, lastIndexOf, lastIndexOfOption, lastIndexOfOption, lastIndexOfSlice, lastIndexOfSliceOption, lastIndexOfSliceOption, lastIndexWhere, lastIndexWhereOption, lastIndexWhereOption, lift, narrow, prefixLength, startsWith, startsWith
arrangeBy, average, containsAll, count, equals, existsUnique, find, findLast, fold, foldLeft, forEachWithIndex, get, hashCode, head, headOption, isDistinct, isEmpty, isOrdered, isSingleValued, iterator, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, narrow, nonEmpty, product, reduce, reduceLeft, reduceLeftOption, reduceOption, reduceRight, reduceRightOption, single, singleOption, size, spliterator, sum, toLinkedMap, toMap, toSortedMap, toSortedMap, unzip, unzip3
collect, collect, contains, corresponds, eq, exists, forAll, forEach, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, narrow, out, out, stderr, stdout, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toString, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector
public static <T> java.util.stream.Collector<T,java.util.ArrayList<T>,Stream<T>> collector()
Collector
which may be used in conjunction with
Stream.collect(java.util.stream.Collector)
to obtain a Stream
.T
- Component type of the Stream.Collector
which collects all the input elements into a
Stream
, in encounter order@SafeVarargs public static <T> Stream<T> concat(java.lang.Iterable<? extends T>... iterables)
T
- Component type.iterables
- The iterablesStream
public static <T> Stream<T> concat(java.lang.Iterable<? extends java.lang.Iterable<? extends T>> iterables)
T
- Component type.iterables
- The iterable of iterablesStream
public static Stream<java.lang.Integer> from(int value)
int
values starting from from
.
The Stream
extends to Integer.MIN_VALUE
when passing Integer.MAX_VALUE
.
value
- a start int valuefrom
public static Stream<java.lang.Integer> from(int value, int step)
int
values starting from value
and spaced by step
.
The Stream
extends to Integer.MIN_VALUE
when passing Integer.MAX_VALUE
.
value
- a start int valuestep
- the step by which to advance on each next valueStream
of int values starting from from
public static Stream<java.lang.Long> from(long value)
long
values starting from from
.
The Stream
extends to Integer.MIN_VALUE
when passing Long.MAX_VALUE
.
value
- a start long valuefrom
public static Stream<java.lang.Long> from(long value, long step)
long
values starting from value
and spaced by step
.
The Stream
extends to Long.MIN_VALUE
when passing Long.MAX_VALUE
.
value
- a start long valuestep
- the step by which to advance on each next valueStream
of long values starting from from
public static <T> Stream<T> continually(java.util.function.Supplier<? extends T> supplier)
T
- value typesupplier
- A Supplier of Stream valuespublic static <T> Stream<T> iterate(T seed, java.util.function.Function<? super T,? extends T> f)
T
- value typeseed
- The first value in the Streamf
- A function to calculate the next value based on the previouspublic static <T> Stream<T> iterate(java.util.function.Supplier<? extends Option<? extends T>> supplier)
Some
for each next value and a None
for the end.
The Supplier
will be invoked only that many times until it returns None
,
and repeated iteration over the stream will produce the same values in the same order,
without any further invocations to the Supplier
.T
- value typesupplier
- A Supplier of iterator valuespublic static <T> Stream<T> cons(T head, java.util.function.Supplier<? extends Stream<? extends T>> tailSupplier)
T
- value typehead
- The head element of the StreamtailSupplier
- A supplier of the tail values. To end the stream, return empty()
.public static <T> Stream<T> empty()
Nil.instance()
.
Note: this method intentionally returns type Stream
and not Nil
. This comes handy when folding.
If you explicitly need type Nil
use Stream.Empty.instance().
T
- Component type of Nil, determined by type inference in the particular context.public static <T> Stream<T> narrow(Stream<? extends T> stream)
Stream<? extends T>
to Stream<T>
by performing a type-safe cast. This is eligible because immutable/read-only
collections are covariant.T
- Component type of the Stream
.stream
- A Stream
.stream
instance as narrowed type Stream<T>
.public static <T> Stream<T> of(T element)
Stream
, i.e. a Stream
of one element.@SafeVarargs public static <T> Stream<T> of(T... elements)
Stream.of(1, 2, 3, 4)
= Nil.instance().prepend(4).prepend(3).prepend(2).prepend(1)
= new Cons(1, new Cons(2, new Cons(3, new Cons(4, Nil.instance()))))
T
- Component type of the Stream.elements
- Zero or more elements.public static <T> Stream<T> tabulate(int n, java.util.function.Function<? super java.lang.Integer,? extends T> f)
n
values of a given Function f
over a range of integer values from 0 to n - 1
.T
- Component type of the Streamn
- The number of elements in the Streamf
- The Function computing element valuesf(0),f(1), ..., f(n - 1)
java.lang.NullPointerException
- if f
is nullpublic static <T> Stream<T> fill(int n, java.util.function.Supplier<? extends T> s)
n
values supplied by a given Supplier s
.T
- Component type of the Streamn
- The number of elements in the Streams
- The Supplier computing element valuesn
, where each element contains the result supplied by s
.java.lang.NullPointerException
- if s
is nullpublic static <T> Stream<T> fill(int n, T element)
n
times the given element
T
- Component type of the Streamn
- The number of elements in the Streamelement
- The elementn
, where each element is the given element
.public static <T> Stream<T> ofAll(java.lang.Iterable<? extends T> elements)
T
- Component type of the Stream.elements
- An Iterable of elements.public static <T> Stream<T> ofAll(java.util.stream.Stream<? extends T> javaStream)
Stream
.T
- Component type of the Stream.javaStream
- A Stream
public static Stream<java.lang.Boolean> ofAll(boolean... elements)
elements
- boolean valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Byte> ofAll(byte... elements)
elements
- byte valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Character> ofAll(char... elements)
elements
- char valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Double> ofAll(double... elements)
elements
- double valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Float> ofAll(float... elements)
elements
- float valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Integer> ofAll(int... elements)
elements
- int valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Long> ofAll(long... elements)
elements
- long valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Short> ofAll(short... elements)
elements
- short valuesjava.lang.NullPointerException
- if elements is nullpublic static Stream<java.lang.Character> range(char from, char toExclusive)
public static Stream<java.lang.Character> rangeBy(char from, char toExclusive, int step)
public static Stream<java.lang.Double> rangeBy(double from, double toExclusive, double step)
public static Stream<java.lang.Integer> range(int from, int toExclusive)
from
, extending to toExclusive - 1
.
Examples:
Stream.range(0, 0) // = Stream()
Stream.range(2, 0) // = Stream()
Stream.range(-2, 2) // = Stream(-2, -1, 0, 1)
from
- the first numbertoExclusive
- the last number + 1Nil
if from >= toExclusive
public static Stream<java.lang.Integer> rangeBy(int from, int toExclusive, int step)
from
, extending to toExclusive - 1
,
with step
.
Examples:
Stream.rangeBy(1, 3, 1) // = Stream(1, 2)
Stream.rangeBy(1, 4, 2) // = Stream(1, 3)
Stream.rangeBy(4, 1, -2) // = Stream(4, 2)
Stream.rangeBy(4, 1, 2) // = Stream()
from
- the first numbertoExclusive
- the last number + 1step
- the stepNil
iffrom >= toInclusive
and step > 0
orfrom <= toInclusive
and step < 0
java.lang.IllegalArgumentException
- if step
is zeropublic static Stream<java.lang.Long> range(long from, long toExclusive)
from
, extending to toExclusive - 1
.
Examples:
Stream.range(0L, 0L) // = Stream()
Stream.range(2L, 0L) // = Stream()
Stream.range(-2L, 2L) // = Stream(-2L, -1L, 0L, 1L)
from
- the first numbertoExclusive
- the last number + 1Nil
if from >= toExclusive
public static Stream<java.lang.Long> rangeBy(long from, long toExclusive, long step)
from
, extending to toExclusive - 1
,
with step
.
Examples:
Stream.rangeBy(1L, 3L, 1L) // = Stream(1L, 2L)
Stream.rangeBy(1L, 4L, 2L) // = Stream(1L, 3L)
Stream.rangeBy(4L, 1L, -2L) // = Stream(4L, 2L)
Stream.rangeBy(4L, 1L, 2L) // = Stream()
from
- the first numbertoExclusive
- the last number + 1step
- the stepNil
iffrom >= toInclusive
and step > 0
orfrom <= toInclusive
and step < 0
java.lang.IllegalArgumentException
- if step
is zeropublic static Stream<java.lang.Character> rangeClosed(char from, char toInclusive)
public static Stream<java.lang.Character> rangeClosedBy(char from, char toInclusive, int step)
public static Stream<java.lang.Double> rangeClosedBy(double from, double toInclusive, double step)
public static Stream<java.lang.Integer> rangeClosed(int from, int toInclusive)
from
, extending to toInclusive
.
Examples:
Stream.rangeClosed(0, 0) // = Stream(0)
Stream.rangeClosed(2, 0) // = Stream()
Stream.rangeClosed(-2, 2) // = Stream(-2, -1, 0, 1, 2)
from
- the first numbertoInclusive
- the last numberNil
if from > toInclusive
public static Stream<java.lang.Integer> rangeClosedBy(int from, int toInclusive, int step)
from
, extending to toInclusive
,
with step
.
Examples:
Stream.rangeClosedBy(1, 3, 1) // = Stream(1, 2, 3)
Stream.rangeClosedBy(1, 4, 2) // = Stream(1, 3)
Stream.rangeClosedBy(4, 1, -2) // = Stream(4, 2)
Stream.rangeClosedBy(4, 1, 2) // = Stream()
from
- the first numbertoInclusive
- the last numberstep
- the stepNil
iffrom > toInclusive
and step > 0
orfrom < toInclusive
and step < 0
java.lang.IllegalArgumentException
- if step
is zeropublic static Stream<java.lang.Long> rangeClosed(long from, long toInclusive)
from
, extending to toInclusive
.
Examples:
Stream.rangeClosed(0L, 0L) // = Stream(0L)
Stream.rangeClosed(2L, 0L) // = Stream()
Stream.rangeClosed(-2L, 2L) // = Stream(-2L, -1L, 0L, 1L, 2L)
from
- the first numbertoInclusive
- the last numberNil
if from > toInclusive
public static Stream<java.lang.Long> rangeClosedBy(long from, long toInclusive, long step)
from
, extending to toInclusive
,
with step
.
Examples:
Stream.rangeClosedBy(1L, 3L, 1L) // = Stream(1L, 2L, 3L)
Stream.rangeClosedBy(1L, 4L, 2L) // = Stream(1L, 3L)
Stream.rangeClosedBy(4L, 1L, -2L) // = Stream(4L, 2L)
Stream.rangeClosedBy(4L, 1L, 2L) // = Stream()
from
- the first numbertoInclusive
- the last numberstep
- the stepNil
iffrom > toInclusive
and step > 0
orfrom < toInclusive
and step < 0
java.lang.IllegalArgumentException
- if step
is zeropublic static <T> Stream<Stream<T>> transpose(Stream<Stream<T>> matrix)
Stream
matrix.T
- matrix element typematrix
- to be transposed.Stream
matrix.java.lang.IllegalArgumentException
- if the row lengths of matrix
differ.
ex: Stream.transpose(Stream(Stream(1,2,3), Stream(4,5,6))) → Stream(Stream(1,4), Stream(2,5), Stream(3,6))
public static <T,U> Stream<U> unfoldRight(T seed, java.util.function.Function<? super T,Option<Tuple2<? extends U,? extends T>>> f)
None
when it's
done generating the Stream, otherwise Some
Tuple
of the element for the next call and the value to add to the
resulting Stream.
Example:
Stream.unfoldRight(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x, x-1)));
// Stream(10, 9, 8, 7, 6, 5, 4, 3, 2, 1))
T
- type of seedsU
- type of unfolded valuesseed
- the start value for the iterationf
- the function to get the next step of the iterationjava.lang.NullPointerException
- if f
is nullpublic static <T,U> Stream<U> unfoldLeft(T seed, java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends U>>> f)
None
when it's
done generating the Stream, otherwise Some
Tuple
of the value to add to the resulting Stream and
the element for the next call.
Example:
Stream.unfoldLeft(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x-1, x)));
// Stream(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
T
- type of seedsU
- type of unfolded valuesseed
- the start value for the iterationf
- the function to get the next step of the iterationjava.lang.NullPointerException
- if f
is nullpublic static <T> Stream<T> unfold(T seed, java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends T>>> f)
None
when it's
done generating the Stream, otherwise Some
Tuple
of the value to add to the resulting Stream and
the element for the next call.
Example:
Stream.unfold(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x-1, x)));
// Stream(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
T
- type of seeds and unfolded valuesseed
- the start value for the iterationf
- the function to get the next step of the iterationjava.lang.NullPointerException
- if f
is nullpublic static <T> Stream<T> continually(T t)
T
- Element typet
- An elementt
's.public abstract Stream<T> append(T element)
Seq
public abstract Stream<T> appendAll(java.lang.Iterable<? extends T> elements)
Seq
public final Stream<T> appendSelf(java.util.function.Function<? super Stream<T>,? extends Stream<T>> mapper)
mapper
function.
Example:
Well known Scala code for Fibonacci infinite sequence
val fibs:Stream[Int] = 0 #:: 1 #:: (fibs zip fibs.tail).map{ t => t._1 + t._2 }
can be transformed to
Stream.of(0, 1).appendSelf(self -> self.zip(self.tail()).map(t -> t._1 + t._2));
mapper
- an mapperpublic final java.util.List<T> asJava()
Seq
List
view on top of this Seq
,
i.e. calling mutators will result in UnsupportedOperationException
at runtime.
The difference to conversion methods toJava*()
is that
java.util.List
view throws UnsupportedOperationException
before
checking method arguments. Java does handle this case inconsistently.public final Stream<T> asJava(java.util.function.Consumer<? super java.util.List<T>> action)
Seq
List
view on top of this Seq
that is passed to the given action
.public final java.util.List<T> asJavaMutable()
Seq
List
view on top of this Seq
,
i.e. all mutator methods of the List
are implemented.asJavaMutable
in interface Seq<T>
Collection
view on this Traversable
.Seq.asJava()
public final Stream<T> asJavaMutable(java.util.function.Consumer<? super java.util.List<T>> action)
Seq
List
view on top of this Seq
that is passed to the given action
.asJavaMutable
in interface LinearSeq<T>
asJavaMutable
in interface Seq<T>
action
- A side-effecting unit of work that operates on a mutable java.util.List
view.java.util.List
view or a new instance of this type, if write operations are performed on the java.util.List
view.Seq.asJavaMutable()
public final <R> Stream<R> collect(PartialFunction<? super T,? extends R> partialFunction)
Traversable
partialFunction
by mapping the elements to type R
.
More specifically, for each of this elements in iteration order first it is checked
partialFunction.isDefinedAt(element)
If the elements makes it through that filter, the mapped instance is added to the result collection
R newElement = partialFunction.apply(element)
Note:If this Traversable
is ordered (i.e. extends Ordered
,
the caller of collect
has to ensure that the elements are comparable (i.e. extend Comparable
).collect
in interface LinearSeq<T>
collect
in interface Seq<T>
collect
in interface Traversable<T>
R
- The new element typepartialFunction
- A function that is not necessarily defined of all elements of this traversable.Traversable
instance containing elements of type R
public final Stream<Stream<T>> combinations()
Seq
Examples:
[].combinations() = [[]]
[1,2,3].combinations() = [
[], // k = 0
[1], [2], [3], // k = 1
[1,2], [1,3], [2,3], // k = 2
[1,2,3] // k = 3
]
combinations
in interface LinearSeq<T>
combinations
in interface Seq<T>
public final Stream<Stream<T>> combinations(int k)
Seq
combinations
in interface LinearSeq<T>
combinations
in interface Seq<T>
k
- Size of subsetspublic final Iterator<Stream<T>> crossProduct(int power)
Seq
Example:
// = ((A,A), (A,B), (A,C), ..., (B,A), (B,B), ..., (Z,Y), (Z,Z))
CharSeq.rangeClosed('A', 'Z').crossProduct(2);
Cartesian power of negative value will return empty iterator.
Example:
// = ()
CharSeq.rangeClosed('A', 'Z').crossProduct(-1);
crossProduct
in interface LinearSeq<T>
crossProduct
in interface Seq<T>
power
- the number of cartesian multiplicationspublic final Stream<T> cycle()
Example:
// = 1, 2, 3, 1, 2, 3, 1, 2, 3, ...
Stream.of(1, 2, 3).cycle();
public final Stream<T> cycle(int count)
count
times.
Example:
// = empty
Stream.of(1, 2, 3).cycle(0);
// = 1, 2, 3
Stream.of(1, 2, 3).cycle(1);
// = 1, 2, 3, 1, 2, 3, 1, 2, 3
Stream.of(1, 2, 3).cycle(3);
count
- the number of cycles to be performedcount
times.public final Stream<T> distinct()
Traversable
equals
.public final Stream<T> distinctBy(java.util.Comparator<? super T> comparator)
Traversable
comparator
.distinctBy
in interface LinearSeq<T>
distinctBy
in interface Seq<T>
distinctBy
in interface Traversable<T>
comparator
- A comparatorTraversable
containing this elements without duplicatespublic final <U> Stream<T> distinctBy(java.util.function.Function<? super T,? extends U> keyExtractor)
Traversable
equals
.
The elements of the result are determined in the order of their occurrence - first match wins.
distinctBy
in interface LinearSeq<T>
distinctBy
in interface Seq<T>
distinctBy
in interface Traversable<T>
U
- key typekeyExtractor
- A key extractorTraversable
containing this elements without duplicatespublic final Stream<T> drop(int n)
Traversable
drop
in interface LinearSeq<T>
drop
in interface Seq<T>
drop
in interface Traversable<T>
n
- The number of elements to drop.public final Stream<T> dropUntil(java.util.function.Predicate<? super T> predicate)
Traversable
dropUntil
in interface LinearSeq<T>
dropUntil
in interface Seq<T>
dropUntil
in interface Traversable<T>
predicate
- A condition tested subsequently for this elements.public final Stream<T> dropWhile(java.util.function.Predicate<? super T> predicate)
Traversable
Note: This is essentially the same as dropUntil(predicate.negate())
.
It is intended to be used with method references, which cannot be negated directly.
dropWhile
in interface LinearSeq<T>
dropWhile
in interface Seq<T>
dropWhile
in interface Traversable<T>
predicate
- A condition tested subsequently for this elements.public final Stream<T> dropRight(int n)
Traversable
dropRight
in interface LinearSeq<T>
dropRight
in interface Seq<T>
dropRight
in interface Traversable<T>
n
- The number of elements to drop.public final Stream<T> dropRightUntil(java.util.function.Predicate<? super T> predicate)
Seq
dropRightUntil
in interface LinearSeq<T>
dropRightUntil
in interface Seq<T>
predicate
- A condition tested subsequently for this elements, starting from the end.public final Stream<T> dropRightWhile(java.util.function.Predicate<? super T> predicate)
Seq
Note: This is essentially the same as dropRightUntil(predicate.negate())
.
It is intended to be used with method references, which cannot be negated directly.
dropRightWhile
in interface LinearSeq<T>
dropRightWhile
in interface Seq<T>
predicate
- A condition tested subsequently for this elements, starting from the end.public final Stream<T> filter(java.util.function.Predicate<? super T> predicate)
Traversable
public final Stream<T> filterNot(java.util.function.Predicate<? super T> predicate)
Traversable
The default implementation is equivalent to
filter(predicate.negate()
public final <U> Stream<U> flatMap(java.util.function.Function<? super T,? extends java.lang.Iterable<? extends U>> mapper)
Traversable
public T apply(java.lang.Integer index)
Seq
Seq
is a partial function which returns the element at the specified index if the
index is valid. It's up to the caller to make sure the index is valid (for instance through
isDefinedAt
).
The behaviour is undefined if the index is out of bounds.
It may throw any RuntimeException
or return an arbitrary value.apply
in interface Seq<T>
apply
in interface Function1<java.lang.Integer,T>
apply
in interface PartialFunction<java.lang.Integer,T>
apply
in interface java.util.function.Function<java.lang.Integer,T>
index
- an indexpublic final T get(int index)
Seq
public final Option<T> getOption(int index)
Seq
public final T getOrElse(int index, T defaultValue)
Seq
public final <C> Map<C,Stream<T>> groupBy(java.util.function.Function<? super T,? extends C> classifier)
Traversable
groupBy
in interface LinearSeq<T>
groupBy
in interface Seq<T>
groupBy
in interface Traversable<T>
C
- classified class typeclassifier
- A function which classifies elements into classesTraversable.arrangeBy(Function)
public final Iterator<Stream<T>> grouped(int size)
Traversable
Traversable
into fixed size blocks.
Let length be the length of this Iterable. Then grouped is defined as follows:
this.isEmpty()
, the resulting Iterator
is empty.size <= length
, the resulting Iterator
will contain length / size
blocks of size
size
and maybe a non-empty block of size length % size
, if there are remaining elements.size > length
, the resulting Iterator
will contain one block of size length
.
[].grouped(1) = []
[].grouped(0) throws
[].grouped(-1) throws
[1,2,3,4].grouped(2) = [[1,2],[3,4]]
[1,2,3,4,5].grouped(2) = [[1,2],[3,4],[5]]
[1,2,3,4].grouped(5) = [[1,2,3,4]]
Please note that grouped(int)
is a special case of Traversable.sliding(int, int), i.e.
grouped(size)
is the same as sliding(size, size)
.public final boolean hasDefiniteSize()
Traversable
This method should be implemented by classes only, i.e. not by interfaces.
hasDefiniteSize
in interface Traversable<T>
public final int indexOf(T element, int from)
Seq
public final Stream<T> init()
Traversable
public final Option<Stream<T>> initOption()
Traversable
Option
.initOption
in interface LinearSeq<T>
initOption
in interface Seq<T>
initOption
in interface Traversable<T>
Some(traversable)
or None
if this is empty.public final Stream<T> insert(int index, T element)
Seq
public final Stream<T> insertAll(int index, java.lang.Iterable<? extends T> elements)
Seq
public final Stream<T> intersperse(T element)
Seq
intersperse
in interface LinearSeq<T>
intersperse
in interface Seq<T>
element
- An element.public final boolean isAsync()
Stream
is computed synchronously.public final boolean isLazy()
Stream
is computed lazily.public final boolean isTraversableAgain()
Traversable
This method should be implemented by classes only, i.e. not by interfaces.
isTraversableAgain
in interface Traversable<T>
public final T last()
Traversable
last
in interface Traversable<T>
public final int lastIndexOf(T element, int end)
Seq
lastIndexOf
in interface Seq<T>
element
- an elementend
- the end indexpublic final int length()
Traversable
Same as Traversable.size()
.
length
in interface Traversable<T>
@Deprecated public boolean isDefinedAt(java.lang.Integer index)
PartialFunction
isDefinedAt
in interface PartialFunction<java.lang.Integer,T>
index
- a potential function argumentpublic final <U> Stream<U> map(java.util.function.Function<? super T,? extends U> mapper)
Traversable
Traversable
to elements of a new type preserving their order, if any.public final Stream<T> padTo(int length, T element)
Seq
Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
padTo
in interface LinearSeq<T>
padTo
in interface Seq<T>
length
- the target lengthelement
- the padding elementelement
so that the resulting sequence has a length of at least length
.public final Stream<T> leftPadTo(int length, T element)
Seq
Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
leftPadTo
in interface Seq<T>
length
- the target lengthelement
- the padding elementelement
so that the resulting sequence has a length of at least length
.public final Stream<T> orElse(java.lang.Iterable<? extends T> other)
Traversable
Traversable
if it is nonempty, otherwise return the alternative.public final Stream<T> orElse(java.util.function.Supplier<? extends java.lang.Iterable<? extends T>> supplier)
Traversable
Traversable
if it is nonempty, otherwise return the result of evaluating supplier.public final Stream<T> patch(int from, java.lang.Iterable<? extends T> that, int replaced)
Seq
public final Tuple2<Stream<T>,Stream<T>> partition(java.util.function.Predicate<? super T> predicate)
Traversable
Traversable
by splitting this elements in two in distinct traversables
according to a predicate.partition
in interface LinearSeq<T>
partition
in interface Seq<T>
partition
in interface Traversable<T>
predicate
- A predicate which classifies an element if it is in the first or the second traversable.Traversable
contains all elements that satisfy the given predicate
, the second Traversable
contains all elements that don't. The original order of elements is preserved.public final Stream<T> peek(java.util.function.Consumer<? super T> action)
Value
action
on the first element if this is an eager implementation.
Performs the given action
on all elements (the first immediately, successive deferred),
if this is a lazy implementation.public final Stream<Stream<T>> permutations()
Seq
Example:
[].permutations() = []
[1,2,3].permutations() = [
[1,2,3],
[1,3,2],
[2,1,3],
[2,3,1],
[3,1,2],
[3,2,1]
]
permutations
in interface LinearSeq<T>
permutations
in interface Seq<T>
public final Stream<T> prepend(T element)
Seq
public final Stream<T> prependAll(java.lang.Iterable<? extends T> elements)
Seq
prependAll
in interface LinearSeq<T>
prependAll
in interface Seq<T>
elements
- An Iterable of elementspublic final Stream<T> remove(T element)
Seq
public final Stream<T> removeFirst(java.util.function.Predicate<T> predicate)
Seq
removeFirst
in interface LinearSeq<T>
removeFirst
in interface Seq<T>
predicate
- an predicatepublic final Stream<T> removeLast(java.util.function.Predicate<T> predicate)
Seq
removeLast
in interface LinearSeq<T>
removeLast
in interface Seq<T>
predicate
- an predicatepublic final Stream<T> removeAt(int index)
Seq
public final Stream<T> removeAll(T element)
Seq
public final Stream<T> removeAll(java.lang.Iterable<? extends T> elements)
Seq
public final Stream<T> replace(T currentElement, T newElement)
Traversable
replace
in interface LinearSeq<T>
replace
in interface Seq<T>
replace
in interface Traversable<T>
currentElement
- An element to be substituted.newElement
- A replacement for currentElement.public final Stream<T> replaceAll(T currentElement, T newElement)
Traversable
replaceAll
in interface LinearSeq<T>
replaceAll
in interface Seq<T>
replaceAll
in interface Traversable<T>
currentElement
- An element to be substituted.newElement
- A replacement for currentElement.public final Stream<T> retainAll(java.lang.Iterable<? extends T> elements)
Traversable
public final Stream<T> reverse()
Seq
public final Stream<T> rotateLeft(int n)
Seq
// = List(3, 4, 5, 1, 2)
List.of(1, 2, 3, 4, 5).rotateLeft(2);
rotateLeft
in interface LinearSeq<T>
rotateLeft
in interface Seq<T>
n
- distance of left rotationpublic final Stream<T> rotateRight(int n)
Seq
// = List(4, 5, 1, 2, 3)
List.of(1, 2, 3, 4, 5).rotateRight(2);
rotateRight
in interface LinearSeq<T>
rotateRight
in interface Seq<T>
n
- distance of right rotationpublic final Stream<T> scan(T zero, java.util.function.BiFunction<? super T,? super T,? extends T> operation)
Traversable
scan
in interface LinearSeq<T>
scan
in interface Seq<T>
scan
in interface Traversable<T>
zero
- neutral element for the operator opoperation
- the associative operator for the scanpublic final <U> Stream<U> scanLeft(U zero, java.util.function.BiFunction<? super U,? super T,? extends U> operation)
Traversable
scanLeft
in interface LinearSeq<T>
scanLeft
in interface Seq<T>
scanLeft
in interface Traversable<T>
U
- the type of the elements in the resulting collectionzero
- the initial valueoperation
- the binary operator applied to the intermediate result and the elementpublic final <U> Stream<U> scanRight(U zero, java.util.function.BiFunction<? super T,? super U,? extends U> operation)
Traversable
scanRight
in interface LinearSeq<T>
scanRight
in interface Seq<T>
scanRight
in interface Traversable<T>
U
- the type of the elements in the resulting collectionzero
- the initial valueoperation
- the binary operator applied to the intermediate result and the elementpublic final Stream<T> shuffle()
Seq
public final Stream<T> shuffle(java.util.Random random)
Seq
public final Stream<T> slice(int beginIndex, int endIndex)
Seq
beginIndex
and extends to the element at index endIndex - 1
.
Examples:
List.of(1, 2, 3, 4).slice(1, 3); // = (2, 3)
List.of(1, 2, 3, 4).slice(0, 4); // = (1, 2, 3, 4)
List.of(1, 2, 3, 4).slice(2, 2); // = ()
List.of(1, 2).slice(1, 0); // = ()
List.of(1, 2).slice(-10, 10); // = (1, 2)
See also Seq.subSequence(int, int)
which throws in some cases instead of returning a sequence.public final Iterator<Stream<T>> slideBy(java.util.function.Function<? super T,?> classifier)
Traversable
Traversable
.
Each window contains elements with the same class, as determined by classifier
. Two consecutive
values in this Traversable
will be in the same window only if classifier
returns equal
values for them. Otherwise, the values will constitute the last element of the previous window and the
first element of the next window.
Examples:
[].slideBy(Function.identity()) = []
[1,2,3,4,4,5].slideBy(Function.identity()) = [[1],[2],[3],[4,4],[5]]
[1,2,3,10,12,5,7,20,29].slideBy(x -> x/10) = [[1,2,3],[10,12],[5,7],[20,29]]
public final Iterator<Stream<T>> sliding(int size)
Traversable
size
and step size 1 over this Traversable
by calling
Traversable.sliding(int, int)
.public final Iterator<Stream<T>> sliding(int size, int step)
Traversable
size
and step
size over this Traversable
.
Examples:
[].sliding(1,1) = []
[1,2,3,4,5].sliding(2,3) = [[1,2],[4,5]]
[1,2,3,4,5].sliding(2,4) = [[1,2],[5]]
[1,2,3,4,5].sliding(2,5) = [[1,2]]
[1,2,3,4].sliding(5,3) = [[1,2,3,4]]
public final Stream<T> sorted()
Seq
Comparable
, a java.lang.ClassCastException
may be thrown.public final Stream<T> sorted(java.util.Comparator<? super T> comparator)
Seq
Comparator
. If this elements are not
Comparable
, a java.lang.ClassCastException
may be thrown.public final <U extends java.lang.Comparable<? super U>> Stream<T> sortBy(java.util.function.Function<? super T,? extends U> mapper)
Seq
mapper
.public final <U> Stream<T> sortBy(java.util.Comparator<? super U> comparator, java.util.function.Function<? super T,? extends U> mapper)
Seq
mapper
.public final Tuple2<Stream<T>,Stream<T>> span(java.util.function.Predicate<? super T> predicate)
Traversable
predicate
and the second element is the remainder.public final Tuple2<Stream<T>,Stream<T>> splitAt(int n)
Seq
splitAt(n)
is equivalent to
Tuple.of(take(n), drop(n))
.public final Tuple2<Stream<T>,Stream<T>> splitAt(java.util.function.Predicate<? super T> predicate)
Seq
Predicate
, e.g. Tuple(init, element+tail).public final Tuple2<Stream<T>,Stream<T>> splitAtInclusive(java.util.function.Predicate<? super T> predicate)
Seq
Predicate
, e.g. Tuple(init+element, tail).splitAtInclusive
in interface Seq<T>
predicate
- An predicateTuple
containing divided sequencespublic final java.lang.String stringPrefix()
Value
stringPrefix
in interface Value<T>
public final Stream<T> subSequence(int beginIndex)
Seq
beginIndex
and extends to the end of this Seq.
Examples:
List.of(1, 2).subSequence(0); // = (1, 2)
List.of(1, 2).subSequence(1); // = (2)
List.of(1, 2).subSequence(2); // = ()
List.of(1, 2).subSequence(10); // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(-10); // throws IndexOutOfBoundsException
See also Seq.drop(int)
which is similar but does not throw.subSequence
in interface LinearSeq<T>
subSequence
in interface Seq<T>
beginIndex
- the beginning index, inclusivepublic final Stream<T> subSequence(int beginIndex, int endIndex)
Seq
beginIndex
and extends to the element at index endIndex - 1
.
Examples:
List.of(1, 2, 3, 4).subSequence(1, 3); // = (2, 3)
List.of(1, 2, 3, 4).subSequence(0, 4); // = (1, 2, 3, 4)
List.of(1, 2, 3, 4).subSequence(2, 2); // = ()
List.of(1, 2).subSequence(1, 0); // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(-10, 1); // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(0, 10); // throws IndexOutOfBoundsException
See also Seq.slice(int, int)
which returns an empty sequence instead of throwing.subSequence
in interface LinearSeq<T>
subSequence
in interface Seq<T>
beginIndex
- the beginning index, inclusiveendIndex
- the end index, exclusivepublic abstract Stream<T> tail()
Traversable
public final Option<Stream<T>> tailOption()
Traversable
Option
.tailOption
in interface LinearSeq<T>
tailOption
in interface Seq<T>
tailOption
in interface Traversable<T>
Some(traversable)
or None
if this is empty.public final Stream<T> take(int n)
Traversable
The result is equivalent to sublist(0, max(0, min(length(), n)))
but does not throw if n < 0
or
n > length()
.
In the case of n < 0
the empty instance is returned, in the case of n > length()
this is returned.
public final Stream<T> takeUntil(java.util.function.Predicate<? super T> predicate)
Traversable
Note: This is essentially the same as takeWhile(predicate.negate())
. It is intended to be used with
method references, which cannot be negated directly.
takeUntil
in interface LinearSeq<T>
takeUntil
in interface Seq<T>
takeUntil
in interface Traversable<T>
predicate
- A condition tested subsequently for this elements.public final Stream<T> takeWhile(java.util.function.Predicate<? super T> predicate)
Traversable
takeWhile
in interface LinearSeq<T>
takeWhile
in interface Seq<T>
takeWhile
in interface Traversable<T>
predicate
- A condition tested subsequently for the contained elements.public final Stream<T> takeRight(int n)
Traversable
The result is equivalent to sublist(max(0, min(length(), length() - n)), n)
, i.e. takeRight will not
throw if n < 0
or n > length()
.
In the case of n < 0
the empty instance is returned, in the case of n > length()
this is returned.
takeRight
in interface LinearSeq<T>
takeRight
in interface Seq<T>
takeRight
in interface Traversable<T>
n
- The number of elements to take.public final Stream<T> takeRightUntil(java.util.function.Predicate<? super T> predicate)
Seq
takeRightUntil
in interface LinearSeq<T>
takeRightUntil
in interface Seq<T>
predicate
- A condition tested subsequently for this elements, starting from the end.public final Stream<T> takeRightWhile(java.util.function.Predicate<? super T> predicate)
Seq
Note: This is essentially the same as takeRightUntil(predicate.negate())
.
It is intended to be used with method references, which cannot be negated directly.
takeRightWhile
in interface LinearSeq<T>
takeRightWhile
in interface Seq<T>
predicate
- A condition tested subsequently for this elements, starting from the end.public final <U> U transform(java.util.function.Function<? super Stream<T>,? extends U> f)
Stream
.U
- Type of transformation resultf
- A transformationU
java.lang.NullPointerException
- if f
is nullpublic final Stream<T> update(int index, T element)
Seq
public final Stream<T> update(int index, java.util.function.Function<? super T,? extends T> updater)
Seq
public final <U> Stream<Tuple2<T,U>> zip(java.lang.Iterable<? extends U> that)
Traversable
The length of the returned traversable is the minimum of the lengths of this traversable and that
iterable.
zip
in interface LinearSeq<T>
zip
in interface Seq<T>
zip
in interface Traversable<T>
U
- The type of the second half of the returned pairs.that
- The Iterable providing the second half of each result pair.that
iterable.public final <U,R> Stream<R> zipWith(java.lang.Iterable<? extends U> that, java.util.function.BiFunction<? super T,? super U,? extends R> mapper)
Traversable
The length of the returned traversable is the minimum of the lengths of this traversable and that
iterable.
zipWith
in interface LinearSeq<T>
zipWith
in interface Seq<T>
zipWith
in interface Traversable<T>
U
- The type of the second parameter of the mapper.R
- The type of the mapped elements.that
- The Iterable providing the second parameter of the mapper.mapper
- a mapper.that
iterable.public final <U> Stream<Tuple2<T,U>> zipAll(java.lang.Iterable<? extends U> iterable, T thisElem, U thatElem)
Traversable
The length of the returned traversable is the maximum of the lengths of this traversable and that
iterable.
Special case: if this traversable is shorter than that elements, and that elements contains duplicates, the resulting traversable may be shorter than the maximum of the lengths of this and that because a traversable contains an element at most once.
If this Traversable is shorter than that, thisElem values are used to fill the result. If that is shorter than this Traversable, thatElem values are used to fill the result.
zipAll
in interface LinearSeq<T>
zipAll
in interface Seq<T>
zipAll
in interface Traversable<T>
U
- The type of the second half of the returned pairs.iterable
- The Iterable providing the second half of each result pair.thisElem
- The element to be used to fill up the result if this traversable is shorter than that.thatElem
- The element to be used to fill up the result if that is shorter than this traversable.public final Stream<Tuple2<T,java.lang.Integer>> zipWithIndex()
Traversable
zipWithIndex
in interface LinearSeq<T>
zipWithIndex
in interface Seq<T>
zipWithIndex
in interface Traversable<T>
public final <U> Stream<U> zipWithIndex(java.util.function.BiFunction<? super T,? super java.lang.Integer,? extends U> mapper)
Traversable
The length of the returned traversable is the minimum of the lengths of this traversable and that
iterable.
zipWithIndex
in interface LinearSeq<T>
zipWithIndex
in interface Seq<T>
zipWithIndex
in interface Traversable<T>
U
- The type of the mapped elements.mapper
- a mapper.that
iterable.public final Stream<T> extend(T next)
Stream
with a constantly repeated value.next
- value with which the stream should be extendedStream
composed from this stream extended with a Stream of provided valuepublic final Stream<T> extend(java.util.function.Supplier<? extends T> nextSupplier)
Stream
with values provided by a Supplier
nextSupplier
- a supplier which will provide values for extending a streamStream
composed from this stream extended with values provided by the supplierpublic final Stream<T> extend(java.util.function.Function<? super T,? extends T> nextFunction)
Stream
with a Stream of values created by applying
consecutively provided Function
to the last element of the original Stream.nextFunction
- a function which calculates the next value basing on the previous valueStream
composed from this stream extended with values calculated by the provided function