Class Stream<T>

  • Type Parameters:
    T - component type of this Stream
    All Implemented Interfaces:
    Foldable<T>, LinearSeq<T>, Seq<T>, Traversable<T>, Function1<java.lang.Integer,​T>, Iterable<T>, PartialFunction<java.lang.Integer,​T>, Value<T>, java.io.Serializable, java.lang.Iterable<T>, java.util.function.Function<java.lang.Integer,​T>
    Direct Known Subclasses:
    Stream.Cons, Stream.Empty

    public abstract class Stream<T>
    extends java.lang.Object
    implements LinearSeq<T>
    An immutable 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.
    Methods to obtain a 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.
    See Also:
    Serialized Form
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class 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
    • Method Summary

      Modifier and Type Method 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.
      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.
      <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 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 element)
      Returns a singleton Stream, i.e.
      static <T> Stream<T> of​(T... elements)
      Creates a Stream of the given elements.
      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 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.lang.Iterable<? extends T> elements)
      Creates a Stream of the given elements.
      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> reject​(java.util.function.Predicate<? super T> predicate)
      Deprecated.
      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​(java.util.function.Predicate<? super T> predicate)
      Deprecated.
      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>>
      Stream<T>
      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.
      <T1,​T2>
      Tuple2<Stream<T1>,​Stream<T2>>
      unzip​(java.util.function.Function<? super T,​Tuple2<? extends T1,​? extends T2>> unzipper)
      Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct sets.
      <T1,​T2,​T3>
      Tuple3<Stream<T1>,​Stream<T2>,​Stream<T3>>
      unzip3​(java.util.function.Function<? super T,​Tuple3<? extends T1,​? extends T2,​? extends T3>> unzipper)
      Unzips this elements by mapping this elements to triples which are subsequently split into three distinct sets.
      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.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
      • Methods inherited from interface io.vavr.Iterable

        to
    • Method Detail

      • collector

        public 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.
        Type Parameters:
        T - Component type of the Stream.
        Returns:
        A io.vavr.collection.Stream Collector.
      • concat

        @SafeVarargs
        public 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.
        Type Parameters:
        T - Component type.
        Parameters:
        iterables - The iterables
        Returns:
        A new Stream
      • concat

        public 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.
        Type Parameters:
        T - Component type.
        Parameters:
        iterables - The iterable of iterables
        Returns:
        A new Stream
      • from

        public static Stream<java.lang.Integer> from​(int value)
        Returns an infinitely long Stream of int values starting from from.

        The Stream extends to Integer.MIN_VALUE when passing Integer.MAX_VALUE.

        Parameters:
        value - a start int value
        Returns:
        a new Stream of int values starting from from
      • from

        public 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.

        The Stream extends to Integer.MIN_VALUE when passing Integer.MAX_VALUE.

        Parameters:
        value - a start int value
        step - the step by which to advance on each next value
        Returns:
        a new Stream of int values starting from from
      • from

        public static Stream<java.lang.Long> from​(long value)
        Returns an infinitely long Stream of long values starting from from.

        The Stream extends to Integer.MIN_VALUE when passing Long.MAX_VALUE.

        Parameters:
        value - a start long value
        Returns:
        a new Stream of long values starting from from
      • from

        public 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.

        The Stream extends to Long.MIN_VALUE when passing Long.MAX_VALUE.

        Parameters:
        value - a start long value
        step - the step by which to advance on each next value
        Returns:
        a new Stream of long values starting from from
      • continually

        public static <T> Stream<T> continually​(java.util.function.Supplier<? extends T> supplier)
        Generates an (theoretically) infinitely long Stream using a value Supplier.
        Type Parameters:
        T - value type
        Parameters:
        supplier - A Supplier of Stream values
        Returns:
        A new Stream
      • iterate

        public 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.
        Type Parameters:
        T - value type
        Parameters:
        seed - The first value in the Stream
        f - A function to calculate the next value based on the previous
        Returns:
        A new Stream
      • iterate

        public 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. 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.
        Type Parameters:
        T - value type
        Parameters:
        supplier - A Supplier of iterator values
        Returns:
        A new Stream
      • cons

        public 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.
        Type Parameters:
        T - value type
        Parameters:
        head - The head element of the Stream
        tailSupplier - A supplier of the tail values. To end the stream, return empty().
        Returns:
        A new Stream
      • empty

        public static <T> Stream<T> empty()
        Returns the single instance of Nil. Convenience method for 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().

        Type Parameters:
        T - Component type of Nil, determined by type inference in the particular context.
        Returns:
        The empty list.
      • narrow

        public static <T> Stream<T> narrow​(Stream<? extends T> stream)
        Narrows a widened Stream<? extends T> to Stream<T> by performing a type-safe cast. This is eligible because immutable/read-only collections are covariant.
        Type Parameters:
        T - Component type of the Stream.
        Parameters:
        stream - A Stream.
        Returns:
        the given stream instance as narrowed type Stream<T>.
      • of

        public static <T> Stream<T> of​(T element)
        Returns a singleton Stream, i.e. a Stream of one element.
        Type Parameters:
        T - The component type
        Parameters:
        element - An element.
        Returns:
        A new Stream instance containing the given element
      • of

        @SafeVarargs
        public static <T> Stream<T> of​(T... elements)
        Creates a Stream of the given 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()))))
        Type Parameters:
        T - Component type of the Stream.
        Parameters:
        elements - Zero or more elements.
        Returns:
        A list containing the given elements in the same order.
      • tabulate

        public 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.
        Type Parameters:
        T - Component type of the Stream
        Parameters:
        n - The number of elements in the Stream
        f - The Function computing element values
        Returns:
        A Stream consisting of elements f(0),f(1), ..., f(n - 1)
        Throws:
        java.lang.NullPointerException - if f is null
      • fill

        public 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.
        Type Parameters:
        T - Component type of the Stream
        Parameters:
        n - The number of elements in the Stream
        s - The Supplier computing element values
        Returns:
        A Stream of size n, where each element contains the result supplied by s.
        Throws:
        java.lang.NullPointerException - if s is null
      • fill

        public static <T> Stream<T> fill​(int n,
                                         T element)
        Returns a Stream containing n times the given element
        Type Parameters:
        T - Component type of the Stream
        Parameters:
        n - The number of elements in the Stream
        element - The element
        Returns:
        A Stream of size n, where each element is the given element.
      • ofAll

        public static <T> Stream<T> ofAll​(java.lang.Iterable<? extends T> elements)
        Creates a Stream of the given elements.
        Type Parameters:
        T - Component type of the Stream.
        Parameters:
        elements - An Iterable of elements.
        Returns:
        A Stream containing the given elements in the same order.
      • ofAll

        public static <T> Stream<T> ofAll​(java.util.stream.Stream<? extends T> javaStream)
        Creates a Stream that contains the elements of the given Stream.
        Type Parameters:
        T - Component type of the Stream.
        Parameters:
        javaStream - A Stream
        Returns:
        A Stream containing the given elements in the same order.
      • ofAll

        public static Stream<java.lang.Boolean> ofAll​(boolean... elements)
        Creates a Stream from boolean values.
        Parameters:
        elements - boolean values
        Returns:
        A new Stream of Boolean values
        Throws:
        java.lang.NullPointerException - if elements is null
      • ofAll

        public static Stream<java.lang.Byte> ofAll​(byte... elements)
        Creates a Stream from byte values.
        Parameters:
        elements - byte values
        Returns:
        A new Stream of Byte values
        Throws:
        java.lang.NullPointerException - if elements is null
      • ofAll

        public static Stream<java.lang.Character> ofAll​(char... elements)
        Creates a Stream from char values.
        Parameters:
        elements - char values
        Returns:
        A new Stream of Character values
        Throws:
        java.lang.NullPointerException - if elements is null
      • ofAll

        public static Stream<java.lang.Double> ofAll​(double... elements)
        Creates a Stream values double values.
        Parameters:
        elements - double values
        Returns:
        A new Stream of Double values
        Throws:
        java.lang.NullPointerException - if elements is null
      • ofAll

        public static Stream<java.lang.Float> ofAll​(float... elements)
        Creates a Stream from float values.
        Parameters:
        elements - float values
        Returns:
        A new Stream of Float values
        Throws:
        java.lang.NullPointerException - if elements is null
      • ofAll

        public static Stream<java.lang.Integer> ofAll​(int... elements)
        Creates a Stream from int values.
        Parameters:
        elements - int values
        Returns:
        A new Stream of Integer values
        Throws:
        java.lang.NullPointerException - if elements is null
      • ofAll

        public static Stream<java.lang.Long> ofAll​(long... elements)
        Creates a Stream from long values.
        Parameters:
        elements - long values
        Returns:
        A new Stream of Long values
        Throws:
        java.lang.NullPointerException - if elements is null
      • ofAll

        public static Stream<java.lang.Short> ofAll​(short... elements)
        Creates a Stream from short values.
        Parameters:
        elements - short values
        Returns:
        A new Stream of Short values
        Throws:
        java.lang.NullPointerException - if elements is null
      • range

        public static Stream<java.lang.Character> range​(char from,
                                                        char toExclusive)
      • rangeBy

        public static Stream<java.lang.Character> rangeBy​(char from,
                                                          char toExclusive,
                                                          int step)
      • rangeBy

        @GwtIncompatible
        public static Stream<java.lang.Double> rangeBy​(double from,
                                                       double toExclusive,
                                                       double step)
      • range

        public static Stream<java.lang.Integer> range​(int from,
                                                      int toExclusive)
        Creates a Stream of int numbers starting from 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)
         
         
        Parameters:
        from - the first number
        toExclusive - the last number + 1
        Returns:
        a range of int values as specified or Nil if from >= toExclusive
      • rangeBy

        public 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.

        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()
         
         
        Parameters:
        from - the first number
        toExclusive - the last number + 1
        step - the step
        Returns:
        a range of long values as specified or Nil if
        from >= toInclusive and step > 0 or
        from <= toInclusive and step < 0
        Throws:
        java.lang.IllegalArgumentException - if step is zero
      • range

        public static Stream<java.lang.Long> range​(long from,
                                                   long toExclusive)
        Creates a Stream of long numbers starting from 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)
         
         
        Parameters:
        from - the first number
        toExclusive - the last number + 1
        Returns:
        a range of long values as specified or Nil if from >= toExclusive
      • rangeBy

        public 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.

        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()
         
         
        Parameters:
        from - the first number
        toExclusive - the last number + 1
        step - the step
        Returns:
        a range of long values as specified or Nil if
        from >= toInclusive and step > 0 or
        from <= toInclusive and step < 0
        Throws:
        java.lang.IllegalArgumentException - if step is zero
      • rangeClosed

        public static Stream<java.lang.Character> rangeClosed​(char from,
                                                              char toInclusive)
      • rangeClosedBy

        public static Stream<java.lang.Character> rangeClosedBy​(char from,
                                                                char toInclusive,
                                                                int step)
      • rangeClosedBy

        @GwtIncompatible
        public static Stream<java.lang.Double> rangeClosedBy​(double from,
                                                             double toInclusive,
                                                             double step)
      • rangeClosed

        public static Stream<java.lang.Integer> rangeClosed​(int from,
                                                            int toInclusive)
        Creates a Stream of int numbers starting from 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)
         
         
        Parameters:
        from - the first number
        toInclusive - the last number
        Returns:
        a range of int values as specified or Nil if from > toInclusive
      • rangeClosedBy

        public 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.

        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()
         
         
        Parameters:
        from - the first number
        toInclusive - the last number
        step - the step
        Returns:
        a range of int values as specified or Nil if
        from > toInclusive and step > 0 or
        from < toInclusive and step < 0
        Throws:
        java.lang.IllegalArgumentException - if step is zero
      • rangeClosed

        public static Stream<java.lang.Long> rangeClosed​(long from,
                                                         long toInclusive)
        Creates a Stream of long numbers starting from 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)
         
         
        Parameters:
        from - the first number
        toInclusive - the last number
        Returns:
        a range of long values as specified or Nil if from > toInclusive
      • rangeClosedBy

        public 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.

        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()
         
         
        Parameters:
        from - the first number
        toInclusive - the last number
        step - the step
        Returns:
        a range of int values as specified or Nil if
        from > toInclusive and step > 0 or
        from < toInclusive and step < 0
        Throws:
        java.lang.IllegalArgumentException - if step is zero
      • transpose

        public static <T> Stream<Stream<T>> transpose​(Stream<Stream<T>> matrix)
        Transposes the rows and columns of a Stream matrix.
        Type Parameters:
        T - matrix element type
        Parameters:
        matrix - to be transposed.
        Returns:
        a transposed Stream matrix.
        Throws:
        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))

      • unfoldRight

        public 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. The function takes the seed at first. The function should return 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))
         
         
        Type Parameters:
        T - type of seeds
        U - type of unfolded values
        Parameters:
        seed - the start value for the iteration
        f - the function to get the next step of the iteration
        Returns:
        a Stream with the values built up by the iteration
        Throws:
        java.lang.NullPointerException - if f is null
      • unfoldLeft

        public 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. The function takes the seed at first. The function should return 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))
         
         
        Type Parameters:
        T - type of seeds
        U - type of unfolded values
        Parameters:
        seed - the start value for the iteration
        f - the function to get the next step of the iteration
        Returns:
        a Stream with the values built up by the iteration
        Throws:
        java.lang.NullPointerException - if f is null
      • unfold

        public 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. The function takes the seed at first. The function should return 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))
         
         
        Type Parameters:
        T - type of seeds and unfolded values
        Parameters:
        seed - the start value for the iteration
        f - the function to get the next step of the iteration
        Returns:
        a Stream with the values built up by the iteration
        Throws:
        java.lang.NullPointerException - if f is null
      • continually

        public static <T> Stream<T> continually​(T t)
        Repeats an element infinitely often.
        Type Parameters:
        T - Element type
        Parameters:
        t - An element
        Returns:
        A new Stream containing infinite t's.
      • append

        public abstract Stream<T> append​(T element)
        Description copied from interface: Seq
        Appends an element to this.
        Specified by:
        append in interface LinearSeq<T>
        Specified by:
        append in interface Seq<T>
        Parameters:
        element - An element
        Returns:
        A new Seq containing the given element appended to this elements
      • appendAll

        public abstract Stream<T> appendAll​(java.lang.Iterable<? extends T> elements)
        Description copied from interface: Seq
        Appends all given elements to this.
        Specified by:
        appendAll in interface LinearSeq<T>
        Specified by:
        appendAll in interface Seq<T>
        Parameters:
        elements - An Iterable of elements
        Returns:
        A new Seq containing the given elements appended to this elements
      • appendSelf

        public final Stream<T> appendSelf​(java.util.function.Function<? super Stream<T>,​? extends Stream<T>> mapper)
        Appends itself to the end of stream with 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));
         
         
        Parameters:
        mapper - an mapper
        Returns:
        a new Stream
      • asJava

        @GwtIncompatible
        public final java.util.List<T> asJava()
        Description copied from interface: Seq
        Creates an immutable 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

        • A view is created in O(1) (constant time) whereas conversion takes O(n) (linear time), with n = collection size.
        • The operations on a view have the same performance characteristics than the underlying persistent Vavr collection whereas the performance characteristics of a converted collection are those of the Java standard collections.
        Please note that our immutable java.util.List view throws UnsupportedOperationException before checking method arguments. Java does handle this case inconsistently.
        Specified by:
        asJava in interface Seq<T>
        Returns:
        A new immutable Collection view on this Traversable.
      • asJava

        @GwtIncompatible
        public final Stream<T> asJava​(java.util.function.Consumer<? super java.util.List<T>> action)
        Description copied from interface: Seq
        Creates an immutable List view on top of this Seq that is passed to the given action.
        Specified by:
        asJava in interface LinearSeq<T>
        Specified by:
        asJava in interface Seq<T>
        Parameters:
        action - A side-effecting unit of work that operates on an immutable java.util.List view.
        Returns:
        this instance
        See Also:
        Seq.asJava()
      • asJavaMutable

        @GwtIncompatible
        public final java.util.List<T> asJavaMutable()
        Description copied from interface: Seq
        Creates a mutable List view on top of this Seq, i.e. all mutator methods of the List are implemented.
        Specified by:
        asJavaMutable in interface Seq<T>
        Returns:
        A new mutable Collection view on this Traversable.
        See Also:
        Seq.asJava()
      • asJavaMutable

        @GwtIncompatible
        public final Stream<T> asJavaMutable​(java.util.function.Consumer<? super java.util.List<T>> action)
        Description copied from interface: Seq
        Creates a mutable List view on top of this Seq that is passed to the given action.
        Specified by:
        asJavaMutable in interface LinearSeq<T>
        Specified by:
        asJavaMutable in interface Seq<T>
        Parameters:
        action - A side-effecting unit of work that operates on a mutable java.util.List view.
        Returns:
        this instance, if only read operations are performed on the java.util.List view or a new instance of this type, if write operations are performed on the java.util.List view.
        See Also:
        Seq.asJavaMutable()
      • collect

        public final <R> Stream<R> collect​(PartialFunction<? super T,​? extends R> partialFunction)
        Description copied from interface: Traversable
        Collects all elements that are in the domain of the given 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).
        Specified by:
        collect in interface LinearSeq<T>
        Specified by:
        collect in interface Seq<T>
        Specified by:
        collect in interface Traversable<T>
        Type Parameters:
        R - The new element type
        Parameters:
        partialFunction - A function that is not necessarily defined of all elements of this traversable.
        Returns:
        A new Traversable instance containing elements of type R
      • combinations

        public final Stream<Stream<T>> combinations()
        Description copied from interface: Seq
        Returns the union of all combinations from k = 0 to length().

        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
         ]
         
         
        Specified by:
        combinations in interface LinearSeq<T>
        Specified by:
        combinations in interface Seq<T>
        Returns:
        the combinations of this
      • combinations

        public final Stream<Stream<T>> combinations​(int k)
        Description copied from interface: Seq
        Returns the k-combination of this traversable, i.e. all subset of this of k distinct elements.
        Specified by:
        combinations in interface LinearSeq<T>
        Specified by:
        combinations in interface Seq<T>
        Parameters:
        k - Size of subsets
        Returns:
        the k-combination of this elements
        See Also:
        Combination
      • crossProduct

        public final Iterator<Stream<T>> crossProduct​(int power)
        Description copied from interface: Seq
        Calculates the n-ary cartesian power (or cross product or simply product) of this.

        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);
         
         
        Specified by:
        crossProduct in interface LinearSeq<T>
        Specified by:
        crossProduct in interface Seq<T>
        Parameters:
        power - the number of cartesian multiplications
        Returns:
        A new Iterator representing the n-ary cartesian power of this
      • cycle

        public final Stream<T> cycle()
        Repeat the elements of this Stream infinitely.

        Example:

         
         // = 1, 2, 3, 1, 2, 3, 1, 2, 3, ...
         Stream.of(1, 2, 3).cycle();
         
         
        Returns:
        A new Stream containing this elements cycled.
      • cycle

        public final Stream<T> cycle​(int count)
        Repeat the elements of this Stream 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);
         
         
        Parameters:
        count - the number of cycles to be performed
        Returns:
        A new Stream containing this elements cycled count times.
      • distinct

        public final Stream<T> distinct()
        Description copied from interface: Traversable
        Returns a new version of this which contains no duplicates. Elements are compared using equals.
        Specified by:
        distinct in interface LinearSeq<T>
        Specified by:
        distinct in interface Seq<T>
        Specified by:
        distinct in interface Traversable<T>
        Returns:
        a new Traversable containing this elements without duplicates
      • distinctBy

        public final Stream<T> distinctBy​(java.util.Comparator<? super T> comparator)
        Description copied from interface: Traversable
        Returns a new version of this which contains no duplicates. Elements are compared using the given comparator.
        Specified by:
        distinctBy in interface LinearSeq<T>
        Specified by:
        distinctBy in interface Seq<T>
        Specified by:
        distinctBy in interface Traversable<T>
        Parameters:
        comparator - A comparator
        Returns:
        a new Traversable containing this elements without duplicates
      • distinctBy

        public final <U> Stream<T> distinctBy​(java.util.function.Function<? super T,​? extends U> keyExtractor)
        Description copied from interface: Traversable
        Returns a new version of this which contains no duplicates. Elements mapped to keys which are compared using equals.

        The elements of the result are determined in the order of their occurrence - first match wins.

        Specified by:
        distinctBy in interface LinearSeq<T>
        Specified by:
        distinctBy in interface Seq<T>
        Specified by:
        distinctBy in interface Traversable<T>
        Type Parameters:
        U - key type
        Parameters:
        keyExtractor - A key extractor
        Returns:
        a new Traversable containing this elements without duplicates
      • drop

        public final Stream<T> drop​(int n)
        Description copied from interface: Traversable
        Drops the first n elements of this or all elements, if this length < n.
        Specified by:
        drop in interface LinearSeq<T>
        Specified by:
        drop in interface Seq<T>
        Specified by:
        drop in interface Traversable<T>
        Parameters:
        n - The number of elements to drop.
        Returns:
        a new instance consisting of all elements of this except the first n ones, or else the empty instance, if this has less than n elements.
      • dropUntil

        public final Stream<T> dropUntil​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        Drops elements until the predicate holds for the current element.
        Specified by:
        dropUntil in interface LinearSeq<T>
        Specified by:
        dropUntil in interface Seq<T>
        Specified by:
        dropUntil in interface Traversable<T>
        Parameters:
        predicate - A condition tested subsequently for this elements.
        Returns:
        a new instance consisting of all elements starting from the first one which does satisfy the given predicate.
      • dropWhile

        public final Stream<T> dropWhile​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        Drops elements while the predicate holds for the current element.

        Note: This is essentially the same as dropUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.

        Specified by:
        dropWhile in interface LinearSeq<T>
        Specified by:
        dropWhile in interface Seq<T>
        Specified by:
        dropWhile in interface Traversable<T>
        Parameters:
        predicate - A condition tested subsequently for this elements.
        Returns:
        a new instance consisting of all elements starting from the first one which does not satisfy the given predicate.
      • dropRight

        public final Stream<T> dropRight​(int n)
        Description copied from interface: Traversable
        Drops the last n elements of this or all elements, if this length < n.
        Specified by:
        dropRight in interface LinearSeq<T>
        Specified by:
        dropRight in interface Seq<T>
        Specified by:
        dropRight in interface Traversable<T>
        Parameters:
        n - The number of elements to drop.
        Returns:
        a new instance consisting of all elements of this except the last n ones, or else the empty instance, if this has less than n elements.
      • dropRightUntil

        public final Stream<T> dropRightUntil​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Seq
        Drops elements until the predicate holds for the current element, starting from the end.
        Specified by:
        dropRightUntil in interface LinearSeq<T>
        Specified by:
        dropRightUntil in interface Seq<T>
        Parameters:
        predicate - A condition tested subsequently for this elements, starting from the end.
        Returns:
        a new instance consisting of all elements until and including the last one which does satisfy the given predicate.
      • dropRightWhile

        public final Stream<T> dropRightWhile​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Seq
        Drops elements while the predicate holds for the current element, starting from the end.

        Note: This is essentially the same as dropRightUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.

        Specified by:
        dropRightWhile in interface LinearSeq<T>
        Specified by:
        dropRightWhile in interface Seq<T>
        Parameters:
        predicate - A condition tested subsequently for this elements, starting from the end.
        Returns:
        a new instance consisting of all elements until and including the last one which does not satisfy the given predicate.
      • filter

        public final Stream<T> filter​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        Returns a new traversable consisting of all elements which satisfy the given predicate.
        Specified by:
        filter in interface LinearSeq<T>
        Specified by:
        filter in interface Seq<T>
        Specified by:
        filter in interface Traversable<T>
        Parameters:
        predicate - A predicate
        Returns:
        a new traversable
      • filterNot

        public final Stream<T> filterNot​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        Returns a new traversable consisting of all elements which do not satisfy the given predicate.

        The default implementation is equivalent to

        filter(predicate.negate()
        Specified by:
        filterNot in interface LinearSeq<T>
        Specified by:
        filterNot in interface Seq<T>
        Specified by:
        filterNot in interface Traversable<T>
        Parameters:
        predicate - A predicate
        Returns:
        a new traversable
      • reject

        @Deprecated
        public final Stream<T> reject​(java.util.function.Predicate<? super T> predicate)
        Deprecated.
        Description copied from interface: Traversable
        Returns a new traversable consisting of all elements which do not satisfy the given predicate.

        The default implementation is equivalent to

        filter(predicate.negate()
        Specified by:
        reject in interface LinearSeq<T>
        Specified by:
        reject in interface Seq<T>
        Specified by:
        reject in interface Traversable<T>
        Parameters:
        predicate - A predicate
        Returns:
        a new traversable
      • flatMap

        public final <U> Stream<U> flatMap​(java.util.function.Function<? super T,​? extends java.lang.Iterable<? extends U>> mapper)
        Description copied from interface: Traversable
        FlatMaps this Traversable.
        Specified by:
        flatMap in interface LinearSeq<T>
        Specified by:
        flatMap in interface Seq<T>
        Specified by:
        flatMap in interface Traversable<T>
        Type Parameters:
        U - The resulting component type.
        Parameters:
        mapper - A mapper
        Returns:
        A new Traversable instance.
      • get

        public final T get​(int index)
        Description copied from interface: Seq
        Returns the element at the specified index.
        Specified by:
        get in interface Seq<T>
        Parameters:
        index - an index
        Returns:
        the element at the given index
      • groupBy

        public final <C> Map<C,​Stream<T>> groupBy​(java.util.function.Function<? super T,​? extends C> classifier)
        Description copied from interface: Traversable
        Groups this elements by classifying the elements.
        Specified by:
        groupBy in interface LinearSeq<T>
        Specified by:
        groupBy in interface Seq<T>
        Specified by:
        groupBy in interface Traversable<T>
        Type Parameters:
        C - classified class type
        Parameters:
        classifier - A function which classifies elements into classes
        Returns:
        A Map containing the grouped elements
        See Also:
        Traversable.arrangeBy(Function)
      • grouped

        public final Iterator<Stream<T>> grouped​(int size)
        Description copied from interface: Traversable
        Groups this Traversable into fixed size blocks.

        Let length be the length of this Iterable. Then grouped is defined as follows:

        • If this.isEmpty(), the resulting Iterator is empty.
        • If 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.
        • If size > length, the resulting Iterator will contain one block of size length.
        Examples:
         
         [].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).
        Specified by:
        grouped in interface LinearSeq<T>
        Specified by:
        grouped in interface Seq<T>
        Specified by:
        grouped in interface Traversable<T>
        Parameters:
        size - a positive block size
        Returns:
        A new Iterator of grouped blocks of the given size
      • hasDefiniteSize

        public final boolean hasDefiniteSize()
        Description copied from interface: Traversable
        Checks if this Traversable is known to have a finite size.

        This method should be implemented by classes only, i.e. not by interfaces.

        Specified by:
        hasDefiniteSize in interface Traversable<T>
        Returns:
        true, if this Traversable is known to have a finite size, false otherwise.
      • indexOf

        public final int indexOf​(T element,
                                 int from)
        Description copied from interface: Seq
        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.
        Specified by:
        indexOf in interface Seq<T>
        Parameters:
        element - an element
        from - start index
        Returns:
        the index of the first occurrence of the given element
      • insert

        public final Stream<T> insert​(int index,
                                      T element)
        Description copied from interface: Seq
        Inserts the given element at the specified index.
        Specified by:
        insert in interface LinearSeq<T>
        Specified by:
        insert in interface Seq<T>
        Parameters:
        index - an index
        element - an element
        Returns:
        a new Seq, where the given element is inserted into this at the given index
      • insertAll

        public final Stream<T> insertAll​(int index,
                                         java.lang.Iterable<? extends T> elements)
        Description copied from interface: Seq
        Inserts the given elements at the specified index.
        Specified by:
        insertAll in interface LinearSeq<T>
        Specified by:
        insertAll in interface Seq<T>
        Parameters:
        index - an index
        elements - An Iterable of elements
        Returns:
        a new Seq, where the given elements are inserted into this at the given index
      • intersperse

        public final Stream<T> intersperse​(T element)
        Description copied from interface: Seq
        Inserts an element between all elements of this Traversable.
        Specified by:
        intersperse in interface LinearSeq<T>
        Specified by:
        intersperse in interface Seq<T>
        Parameters:
        element - An element.
        Returns:
        an interspersed version of this
      • isAsync

        public final boolean isAsync()
        A Stream is computed synchronously.
        Specified by:
        isAsync in interface Value<T>
        Returns:
        false
      • isLazy

        public final boolean isLazy()
        A Stream is computed lazily.
        Specified by:
        isLazy in interface Value<T>
        Returns:
        true
      • isTraversableAgain

        public final boolean isTraversableAgain()
        Description copied from interface: Traversable
        Checks if this Traversable can be repeatedly traversed.

        This method should be implemented by classes only, i.e. not by interfaces.

        Specified by:
        isTraversableAgain in interface Traversable<T>
        Returns:
        true, if this Traversable is known to be traversable repeatedly, false otherwise.
      • lastIndexOf

        public final int lastIndexOf​(T element,
                                     int end)
        Description copied from interface: Seq
        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.
        Specified by:
        lastIndexOf in interface Seq<T>
        Parameters:
        element - an element
        end - the end index
        Returns:
        the index of the last occurrence of the given element
      • length

        public final int length()
        Description copied from interface: Traversable
        Computes the number of elements of this Traversable.

        Same as Traversable.size().

        Specified by:
        length in interface Traversable<T>
        Returns:
        the number of elements
      • map

        public final <U> Stream<U> map​(java.util.function.Function<? super T,​? extends U> mapper)
        Description copied from interface: Traversable
        Maps the elements of this Traversable to elements of a new type preserving their order, if any.
        Specified by:
        map in interface LinearSeq<T>
        Specified by:
        map in interface Seq<T>
        Specified by:
        map in interface Traversable<T>
        Specified by:
        map in interface Value<T>
        Type Parameters:
        U - Component type of the target Traversable
        Parameters:
        mapper - A mapper.
        Returns:
        a mapped Traversable
      • padTo

        public final Stream<T> padTo​(int length,
                                     T element)
        Description copied from interface: Seq
        A copy of this sequence with an element appended until a given target length is reached.

        Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.

        Specified by:
        padTo in interface LinearSeq<T>
        Specified by:
        padTo in interface Seq<T>
        Parameters:
        length - the target length
        element - the padding element
        Returns:
        a new sequence consisting of all elements of this sequence followed by the minimal number of occurrences of element so that the resulting sequence has a length of at least length.
      • leftPadTo

        public final Stream<T> leftPadTo​(int length,
                                         T element)
        Description copied from interface: Seq
        A copy of this sequence with an element prepended until a given target length is reached.

        Note: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.

        Specified by:
        leftPadTo in interface Seq<T>
        Parameters:
        length - the target length
        element - the padding element
        Returns:
        a new sequence consisting of all elements of this sequence prepended by the minimal number of occurrences of element so that the resulting sequence has a length of at least length.
      • orElse

        public final Stream<T> orElse​(java.lang.Iterable<? extends T> other)
        Description copied from interface: Traversable
        Returns this Traversable if it is nonempty, otherwise return the alternative.
        Specified by:
        orElse in interface LinearSeq<T>
        Specified by:
        orElse in interface Seq<T>
        Specified by:
        orElse in interface Traversable<T>
        Parameters:
        other - An alternative Traversable
        Returns:
        this Traversable if it is nonempty, otherwise return the alternative.
      • orElse

        public final Stream<T> orElse​(java.util.function.Supplier<? extends java.lang.Iterable<? extends T>> supplier)
        Description copied from interface: Traversable
        Returns this Traversable if it is nonempty, otherwise return the result of evaluating supplier.
        Specified by:
        orElse in interface LinearSeq<T>
        Specified by:
        orElse in interface Seq<T>
        Specified by:
        orElse in interface Traversable<T>
        Parameters:
        supplier - An alternative Traversable supplier
        Returns:
        this Traversable if it is nonempty, otherwise return the result of evaluating supplier.
      • patch

        public final Stream<T> patch​(int from,
                                     java.lang.Iterable<? extends T> that,
                                     int replaced)
        Description copied from interface: Seq
        Produces a new list where a slice of elements in this list is replaced by another sequence.
        Specified by:
        patch in interface LinearSeq<T>
        Specified by:
        patch in interface Seq<T>
        Parameters:
        from - the index of the first replaced element
        that - sequence for replacement
        replaced - the number of elements to drop in the original list
        Returns:
        a new sequence.
      • partition

        public final Tuple2<Stream<T>,​Stream<T>> partition​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        Creates a partition of this Traversable by splitting this elements in two in distinct traversables according to a predicate.
        Specified by:
        partition in interface LinearSeq<T>
        Specified by:
        partition in interface Seq<T>
        Specified by:
        partition in interface Traversable<T>
        Parameters:
        predicate - A predicate which classifies an element if it is in the first or the second traversable.
        Returns:
        A disjoint union of two traversables. The first 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.
      • peek

        public final Stream<T> peek​(java.util.function.Consumer<? super T> action)
        Description copied from interface: Value
        Performs the given 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.
        Specified by:
        peek in interface LinearSeq<T>
        Specified by:
        peek in interface Seq<T>
        Specified by:
        peek in interface Traversable<T>
        Specified by:
        peek in interface Value<T>
        Parameters:
        action - The action that will be performed on the element(s).
        Returns:
        this instance
      • permutations

        public final Stream<Stream<T>> permutations()
        Description copied from interface: Seq
        Computes all unique permutations.

        Example:

         
         [].permutations() = []
        
         [1,2,3].permutations() = [
           [1,2,3],
           [1,3,2],
           [2,1,3],
           [2,3,1],
           [3,1,2],
           [3,2,1]
         ]
         
         
        Specified by:
        permutations in interface LinearSeq<T>
        Specified by:
        permutations in interface Seq<T>
        Returns:
        this unique permutations
      • prepend

        public final Stream<T> prepend​(T element)
        Description copied from interface: Seq
        Prepends an element to this.
        Specified by:
        prepend in interface LinearSeq<T>
        Specified by:
        prepend in interface Seq<T>
        Parameters:
        element - An element
        Returns:
        A new Seq containing the given element prepended to this elements
      • prependAll

        public final Stream<T> prependAll​(java.lang.Iterable<? extends T> elements)
        Description copied from interface: Seq
        Prepends all given elements to this.
        Specified by:
        prependAll in interface LinearSeq<T>
        Specified by:
        prependAll in interface Seq<T>
        Parameters:
        elements - An Iterable of elements
        Returns:
        A new Seq containing the given elements prepended to this elements
      • remove

        public final Stream<T> remove​(T element)
        Description copied from interface: Seq
        Removes the first occurrence of the given element.
        Specified by:
        remove in interface LinearSeq<T>
        Specified by:
        remove in interface Seq<T>
        Parameters:
        element - An element to be removed from this Seq.
        Returns:
        a Seq containing all elements of this without the first occurrence of the given element.
      • removeFirst

        public final Stream<T> removeFirst​(java.util.function.Predicate<T> predicate)
        Description copied from interface: Seq
        Removes the first occurrence that satisfy predicate
        Specified by:
        removeFirst in interface LinearSeq<T>
        Specified by:
        removeFirst in interface Seq<T>
        Parameters:
        predicate - an predicate
        Returns:
        a new Seq
      • removeLast

        public final Stream<T> removeLast​(java.util.function.Predicate<T> predicate)
        Description copied from interface: Seq
        Removes the last occurrence that satisfy predicate
        Specified by:
        removeLast in interface LinearSeq<T>
        Specified by:
        removeLast in interface Seq<T>
        Parameters:
        predicate - an predicate
        Returns:
        a new Seq
      • removeAt

        public final Stream<T> removeAt​(int index)
        Description copied from interface: Seq
        Removes the element at the specified position in this sequence. Shifts any subsequent elements to the left (subtracts one from their indices).
        Specified by:
        removeAt in interface LinearSeq<T>
        Specified by:
        removeAt in interface Seq<T>
        Parameters:
        index - position of element to remove
        Returns:
        a sequence containing all elements of this without the element at the specified position.
      • removeAll

        public final Stream<T> removeAll​(T element)
        Description copied from interface: Seq
        Removes all occurrences of the given element.
        Specified by:
        removeAll in interface LinearSeq<T>
        Specified by:
        removeAll in interface Seq<T>
        Parameters:
        element - An element to be removed from this Seq.
        Returns:
        a Seq containing all elements of this but not the given element.
      • removeAll

        public final Stream<T> removeAll​(java.lang.Iterable<? extends T> elements)
        Description copied from interface: Seq
        Removes all occurrences of the given elements.
        Specified by:
        removeAll in interface LinearSeq<T>
        Specified by:
        removeAll in interface Seq<T>
        Parameters:
        elements - Elements to be removed from this Seq.
        Returns:
        a Seq containing all elements of this but none of the given elements.
      • removeAll

        @Deprecated
        public final Stream<T> removeAll​(java.util.function.Predicate<? super T> predicate)
        Deprecated.
        Description copied from interface: Seq
        Returns a new Seq consisting of all elements which do not satisfy the given predicate.
        Specified by:
        removeAll in interface LinearSeq<T>
        Specified by:
        removeAll in interface Seq<T>
        Parameters:
        predicate - the predicate used to test elements
        Returns:
        a new Seq
      • replace

        public final Stream<T> replace​(T currentElement,
                                       T newElement)
        Description copied from interface: Traversable
        Replaces the first occurrence (if exists) of the given currentElement with newElement.
        Specified by:
        replace in interface LinearSeq<T>
        Specified by:
        replace in interface Seq<T>
        Specified by:
        replace in interface Traversable<T>
        Parameters:
        currentElement - An element to be substituted.
        newElement - A replacement for currentElement.
        Returns:
        a Traversable containing all elements of this where the first occurrence of currentElement is replaced with newElement.
      • replaceAll

        public final Stream<T> replaceAll​(T currentElement,
                                          T newElement)
        Description copied from interface: Traversable
        Replaces all occurrences of the given currentElement with newElement.
        Specified by:
        replaceAll in interface LinearSeq<T>
        Specified by:
        replaceAll in interface Seq<T>
        Specified by:
        replaceAll in interface Traversable<T>
        Parameters:
        currentElement - An element to be substituted.
        newElement - A replacement for currentElement.
        Returns:
        a Traversable containing all elements of this where all occurrences of currentElement are replaced with newElement.
      • retainAll

        public final Stream<T> retainAll​(java.lang.Iterable<? extends T> elements)
        Description copied from interface: Traversable
        Keeps all occurrences of the given elements from this.
        Specified by:
        retainAll in interface LinearSeq<T>
        Specified by:
        retainAll in interface Seq<T>
        Specified by:
        retainAll in interface Traversable<T>
        Parameters:
        elements - Elements to be kept.
        Returns:
        a Traversable containing all occurrences of the given elements.
      • reverse

        public final Stream<T> reverse()
        Description copied from interface: Seq
        Reverses the order of elements.
        Specified by:
        reverse in interface LinearSeq<T>
        Specified by:
        reverse in interface Seq<T>
        Returns:
        the reversed elements.
      • rotateLeft

        public final Stream<T> rotateLeft​(int n)
        Description copied from interface: Seq
        Circular rotates the elements by the specified distance to the left direction.
        
         // = List(3, 4, 5, 1, 2)
         List.of(1, 2, 3, 4, 5).rotateLeft(2);
         
        Specified by:
        rotateLeft in interface LinearSeq<T>
        Specified by:
        rotateLeft in interface Seq<T>
        Parameters:
        n - distance of left rotation
        Returns:
        the rotated elements.
      • rotateRight

        public final Stream<T> rotateRight​(int n)
        Description copied from interface: Seq
        Circular rotates the elements by the specified distance to the right direction.
        
         // = List(4, 5, 1, 2, 3)
         List.of(1, 2, 3, 4, 5).rotateRight(2);
         
        Specified by:
        rotateRight in interface LinearSeq<T>
        Specified by:
        rotateRight in interface Seq<T>
        Parameters:
        n - distance of right rotation
        Returns:
        the rotated elements.
      • scan

        public final Stream<T> scan​(T zero,
                                    java.util.function.BiFunction<? super T,​? super T,​? extends T> operation)
        Description copied from interface: Traversable
        Computes a prefix scan of the elements of the collection. Note: The neutral element z may be applied more than once.
        Specified by:
        scan in interface LinearSeq<T>
        Specified by:
        scan in interface Seq<T>
        Specified by:
        scan in interface Traversable<T>
        Parameters:
        zero - neutral element for the operator op
        operation - the associative operator for the scan
        Returns:
        a new traversable collection containing the prefix scan of the elements in this traversable collection
      • scanLeft

        public final <U> Stream<U> scanLeft​(U zero,
                                            java.util.function.BiFunction<? super U,​? super T,​? extends U> operation)
        Description copied from interface: Traversable
        Produces a collection containing cumulative results of applying the operator going left to right. Note: will not terminate for infinite-sized collections. Note: might return different results for different runs, unless the underlying collection type is ordered.
        Specified by:
        scanLeft in interface LinearSeq<T>
        Specified by:
        scanLeft in interface Seq<T>
        Specified by:
        scanLeft in interface Traversable<T>
        Type Parameters:
        U - the type of the elements in the resulting collection
        Parameters:
        zero - the initial value
        operation - the binary operator applied to the intermediate result and the element
        Returns:
        collection with intermediate results
      • scanRight

        public final <U> Stream<U> scanRight​(U zero,
                                             java.util.function.BiFunction<? super T,​? super U,​? extends U> operation)
        Description copied from interface: Traversable
        Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result. Note: will not terminate for infinite-sized collections. Note: might return different results for different runs, unless the underlying collection type is ordered.
        Specified by:
        scanRight in interface LinearSeq<T>
        Specified by:
        scanRight in interface Seq<T>
        Specified by:
        scanRight in interface Traversable<T>
        Type Parameters:
        U - the type of the elements in the resulting collection
        Parameters:
        zero - the initial value
        operation - the binary operator applied to the intermediate result and the element
        Returns:
        collection with intermediate results
      • shuffle

        public final Stream<T> shuffle()
        Description copied from interface: Seq
        Randomize the order of the elements in the current sequence.
        Specified by:
        shuffle in interface LinearSeq<T>
        Specified by:
        shuffle in interface Seq<T>
        Returns:
        a sequence with the same elements as the current sequence in a random order.
      • shuffle

        public final Stream<T> shuffle​(java.util.Random random)
        Description copied from interface: Seq
        Randomize the order of the elements in the current sequence using the given source of randomness.
        Specified by:
        shuffle in interface LinearSeq<T>
        Specified by:
        shuffle in interface Seq<T>
        Parameters:
        random - A random number generator
        Returns:
        a sequence with the same elements as the current sequence in a random order.
      • slice

        public final Stream<T> slice​(int beginIndex,
                                     int endIndex)
        Description copied from interface: Seq
        Returns a Seq that is a slice of this. The slice begins with the element at the specified 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.
        Specified by:
        slice in interface LinearSeq<T>
        Specified by:
        slice in interface Seq<T>
        Parameters:
        beginIndex - the beginning index, inclusive
        endIndex - the end index, exclusive
        Returns:
        the specified slice
      • slideBy

        public final Iterator<Stream<T>> slideBy​(java.util.function.Function<? super T,​?> classifier)
        Description copied from interface: Traversable
        Slides a non-overlapping window of a variable size over this 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]]
         
        Specified by:
        slideBy in interface LinearSeq<T>
        Specified by:
        slideBy in interface Seq<T>
        Specified by:
        slideBy in interface Traversable<T>
        Parameters:
        classifier - A function which classifies elements into classes
        Returns:
        A new Iterator of windows of the grouped elements
      • sliding

        public final Iterator<Stream<T>> sliding​(int size,
                                                 int step)
        Description copied from interface: Traversable
        Slides a window of a specific 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],[4]]
         
         
        Specified by:
        sliding in interface LinearSeq<T>
        Specified by:
        sliding in interface Seq<T>
        Specified by:
        sliding in interface Traversable<T>
        Parameters:
        size - a positive window size
        step - a positive step size
        Returns:
        a new Iterator of windows of a specific size using a specific step size
      • sorted

        public final Stream<T> sorted()
        Description copied from interface: Seq
        Sorts this elements according to their natural order. If this elements are not Comparable, a java.lang.ClassCastException may be thrown.
        Specified by:
        sorted in interface LinearSeq<T>
        Specified by:
        sorted in interface Seq<T>
        Returns:
        A sorted version of this
      • sorted

        public final Stream<T> sorted​(java.util.Comparator<? super T> comparator)
        Description copied from interface: Seq
        Sorts this elements according to the provided Comparator. If this elements are not Comparable, a java.lang.ClassCastException may be thrown.
        Specified by:
        sorted in interface LinearSeq<T>
        Specified by:
        sorted in interface Seq<T>
        Parameters:
        comparator - A comparator
        Returns:
        a sorted version of this
      • sortBy

        public final <U extends java.lang.Comparable<? super U>> Stream<T> sortBy​(java.util.function.Function<? super T,​? extends U> mapper)
        Description copied from interface: Seq
        Sorts this elements by comparing the elements in a different domain, using the given mapper.
        Specified by:
        sortBy in interface LinearSeq<T>
        Specified by:
        sortBy in interface Seq<T>
        Type Parameters:
        U - The domain where elements are compared
        Parameters:
        mapper - A mapper
        Returns:
        a sorted version of this
      • sortBy

        public final <U> Stream<T> sortBy​(java.util.Comparator<? super U> comparator,
                                          java.util.function.Function<? super T,​? extends U> mapper)
        Description copied from interface: Seq
        Sorts this elements by comparing the elements in a different domain, using the given mapper.
        Specified by:
        sortBy in interface LinearSeq<T>
        Specified by:
        sortBy in interface Seq<T>
        Type Parameters:
        U - The domain where elements are compared
        Parameters:
        comparator - A comparator
        mapper - A mapper
        Returns:
        a sorted version of this
      • span

        public final Tuple2<Stream<T>,​Stream<T>> span​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        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.
        Specified by:
        span in interface LinearSeq<T>
        Specified by:
        span in interface Seq<T>
        Specified by:
        span in interface Traversable<T>
        Parameters:
        predicate - A predicate.
        Returns:
        a Tuple containing the longest prefix of elements that satisfy p and the remainder.
      • splitAt

        public final Tuple2<Stream<T>,​Stream<T>> splitAt​(int n)
        Description copied from interface: Seq
        Splits a Seq at the specified index. The result of splitAt(n) is equivalent to Tuple.of(take(n), drop(n)).
        Specified by:
        splitAt in interface Seq<T>
        Parameters:
        n - An index.
        Returns:
        A Tuple containing the first n and the remaining elements.
      • splitAt

        public final Tuple2<Stream<T>,​Stream<T>> splitAt​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Seq
        Splits a sequence at the first element which satisfies the Predicate, e.g. Tuple(init, element+tail).
        Specified by:
        splitAt in interface Seq<T>
        Parameters:
        predicate - An predicate
        Returns:
        A Tuple containing divided sequences
      • splitAtInclusive

        public final Tuple2<Stream<T>,​Stream<T>> splitAtInclusive​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Seq
        Splits a sequence at the first element which satisfies the Predicate, e.g. Tuple(init+element, tail).
        Specified by:
        splitAtInclusive in interface Seq<T>
        Parameters:
        predicate - An predicate
        Returns:
        A Tuple containing divided sequences
      • stringPrefix

        public final java.lang.String stringPrefix()
        Description copied from interface: Value
        Returns the name of this Value type, which is used by toString().
        Specified by:
        stringPrefix in interface Value<T>
        Returns:
        This type name.
      • subSequence

        public final Stream<T> subSequence​(int beginIndex)
        Description copied from interface: Seq
        Returns a Seq that is a subsequence of this. The subsequence begins with the element at the specified 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.
        Specified by:
        subSequence in interface LinearSeq<T>
        Specified by:
        subSequence in interface Seq<T>
        Parameters:
        beginIndex - the beginning index, inclusive
        Returns:
        the specified subsequence
      • subSequence

        public final Stream<T> subSequence​(int beginIndex,
                                           int endIndex)
        Description copied from interface: Seq
        Returns a Seq that is a subsequence of this. The subsequence begins with the element at the specified 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.
        Specified by:
        subSequence in interface LinearSeq<T>
        Specified by:
        subSequence in interface Seq<T>
        Parameters:
        beginIndex - the beginning index, inclusive
        endIndex - the end index, exclusive
        Returns:
        the specified subsequence
      • tail

        public abstract Stream<T> tail()
        Description copied from interface: Traversable
        Drops the first element of a non-empty Traversable.
        Specified by:
        tail in interface LinearSeq<T>
        Specified by:
        tail in interface Seq<T>
        Specified by:
        tail in interface Traversable<T>
        Returns:
        A new instance of Traversable containing all elements except the first.
      • take

        public final Stream<T> take​(int n)
        Description copied from interface: Traversable
        Takes the first n elements of this or all elements, if this length < n.

        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.

        Specified by:
        take in interface LinearSeq<T>
        Specified by:
        take in interface Seq<T>
        Specified by:
        take in interface Traversable<T>
        Parameters:
        n - The number of elements to take.
        Returns:
        A new instance consisting of the first n elements of this or all elements, if this has less than n elements.
      • takeUntil

        public final Stream<T> takeUntil​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        Takes elements until the predicate holds for the current element.

        Note: This is essentially the same as takeWhile(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.

        Specified by:
        takeUntil in interface LinearSeq<T>
        Specified by:
        takeUntil in interface Seq<T>
        Specified by:
        takeUntil in interface Traversable<T>
        Parameters:
        predicate - A condition tested subsequently for this elements.
        Returns:
        a new instance consisting of all elements before the first one which does satisfy the given predicate.
      • takeWhile

        public final Stream<T> takeWhile​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Traversable
        Takes elements while the predicate holds for the current element.
        Specified by:
        takeWhile in interface LinearSeq<T>
        Specified by:
        takeWhile in interface Seq<T>
        Specified by:
        takeWhile in interface Traversable<T>
        Parameters:
        predicate - A condition tested subsequently for the contained elements.
        Returns:
        a new instance consisting of all elements before the first one which does not satisfy the given predicate.
      • takeRight

        public final Stream<T> takeRight​(int n)
        Description copied from interface: Traversable
        Takes the last n elements of this or all elements, if this length < n.

        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.

        Specified by:
        takeRight in interface LinearSeq<T>
        Specified by:
        takeRight in interface Seq<T>
        Specified by:
        takeRight in interface Traversable<T>
        Parameters:
        n - The number of elements to take.
        Returns:
        A new instance consisting of the last n elements of this or all elements, if this has less than n elements.
      • takeRightUntil

        public final Stream<T> takeRightUntil​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Seq
        Takes elements until the predicate holds for the current element, starting from the end.
        Specified by:
        takeRightUntil in interface LinearSeq<T>
        Specified by:
        takeRightUntil in interface Seq<T>
        Parameters:
        predicate - A condition tested subsequently for this elements, starting from the end.
        Returns:
        a new instance consisting of all elements after the last one which does satisfy the given predicate.
      • takeRightWhile

        public final Stream<T> takeRightWhile​(java.util.function.Predicate<? super T> predicate)
        Description copied from interface: Seq
        Takes elements while the predicate holds for the current element, starting from the end.

        Note: This is essentially the same as takeRightUntil(predicate.negate()). It is intended to be used with method references, which cannot be negated directly.

        Specified by:
        takeRightWhile in interface LinearSeq<T>
        Specified by:
        takeRightWhile in interface Seq<T>
        Parameters:
        predicate - A condition tested subsequently for this elements, starting from the end.
        Returns:
        a new instance consisting of all elements after the last one which does not satisfy the given predicate.
      • transform

        public final <U> U transform​(java.util.function.Function<? super Stream<T>,​? extends U> f)
        Transforms this Stream.
        Type Parameters:
        U - Type of transformation result
        Parameters:
        f - A transformation
        Returns:
        An instance of type U
        Throws:
        java.lang.NullPointerException - if f is null
      • unzip

        public final <T1,​T2> Tuple2<Stream<T1>,​Stream<T2>> unzip​(java.util.function.Function<? super T,​Tuple2<? extends T1,​? extends T2>> unzipper)
        Description copied from interface: Traversable
        Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct sets.
        Specified by:
        unzip in interface LinearSeq<T>
        Specified by:
        unzip in interface Seq<T>
        Specified by:
        unzip in interface Traversable<T>
        Type Parameters:
        T1 - 1st element type of a pair returned by unzipper
        T2 - 2nd element type of a pair returned by unzipper
        Parameters:
        unzipper - a function which converts elements of this to pairs
        Returns:
        A pair of set containing elements split by unzipper
      • unzip3

        public final <T1,​T2,​T3> Tuple3<Stream<T1>,​Stream<T2>,​Stream<T3>> unzip3​(java.util.function.Function<? super T,​Tuple3<? extends T1,​? extends T2,​? extends T3>> unzipper)
        Description copied from interface: Traversable
        Unzips this elements by mapping this elements to triples which are subsequently split into three distinct sets.
        Specified by:
        unzip3 in interface Seq<T>
        Specified by:
        unzip3 in interface Traversable<T>
        Type Parameters:
        T1 - 1st element type of a triplet returned by unzipper
        T2 - 2nd element type of a triplet returned by unzipper
        T3 - 3rd element type of a triplet returned by unzipper
        Parameters:
        unzipper - a function which converts elements of this to pairs
        Returns:
        A triplet of set containing elements split by unzipper
      • update

        public final Stream<T> update​(int index,
                                      T element)
        Description copied from interface: Seq
        Updates the given element at the specified index.
        Specified by:
        update in interface LinearSeq<T>
        Specified by:
        update in interface Seq<T>
        Parameters:
        index - an index
        element - an element
        Returns:
        a new Seq consisting of all previous elements, with a single one (at the given index), changed to the new value.
      • update

        public final Stream<T> update​(int index,
                                      java.util.function.Function<? super T,​? extends T> updater)
        Description copied from interface: Seq
        Updates the given element at the specified index using the specified function.
        Specified by:
        update in interface LinearSeq<T>
        Specified by:
        update in interface Seq<T>
        Parameters:
        index - an index
        updater - a function transforming the previous value
        Returns:
        a new Seq consisting of all previous elements, with a single one (at the given index), changed to the new value.
      • zip

        public final <U> Stream<Tuple2<T,​U>> zip​(java.lang.Iterable<? extends U> that)
        Description copied from interface: Traversable
        Returns a traversable formed from this traversable and another Iterable collection by combining corresponding elements in pairs. If one of the two iterables is longer than the other, its remaining elements are ignored.

        The length of the returned traversable is the minimum of the lengths of this traversable and that iterable.

        Specified by:
        zip in interface LinearSeq<T>
        Specified by:
        zip in interface Seq<T>
        Specified by:
        zip in interface Traversable<T>
        Type Parameters:
        U - The type of the second half of the returned pairs.
        Parameters:
        that - The Iterable providing the second half of each result pair.
        Returns:
        a new traversable containing pairs consisting of corresponding elements of this traversable and that iterable.
      • zipWith

        public final <U,​R> Stream<R> zipWith​(java.lang.Iterable<? extends U> that,
                                                   java.util.function.BiFunction<? super T,​? super U,​? extends R> mapper)
        Description copied from interface: Traversable
        Returns a traversable formed from this traversable and another Iterable collection by mapping elements. If one of the two iterables is longer than the other, its remaining elements are ignored.

        The length of the returned traversable is the minimum of the lengths of this traversable and that iterable.

        Specified by:
        zipWith in interface LinearSeq<T>
        Specified by:
        zipWith in interface Seq<T>
        Specified by:
        zipWith in interface Traversable<T>
        Type Parameters:
        U - The type of the second parameter of the mapper.
        R - The type of the mapped elements.
        Parameters:
        that - The Iterable providing the second parameter of the mapper.
        mapper - a mapper.
        Returns:
        a new traversable containing mapped elements of this traversable and that iterable.
      • zipAll

        public final <U> Stream<Tuple2<T,​U>> zipAll​(java.lang.Iterable<? extends U> iterable,
                                                          T thisElem,
                                                          U thatElem)
        Description copied from interface: Traversable
        Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

        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.

        Specified by:
        zipAll in interface LinearSeq<T>
        Specified by:
        zipAll in interface Seq<T>
        Specified by:
        zipAll in interface Traversable<T>
        Type Parameters:
        U - The type of the second half of the returned pairs.
        Parameters:
        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.
        Returns:
        A new traversable containing pairs consisting of corresponding elements of this traversable and that.
      • zipWithIndex

        public final Stream<Tuple2<T,​java.lang.Integer>> zipWithIndex()
        Description copied from interface: Traversable
        Zips this traversable with its indices.
        Specified by:
        zipWithIndex in interface LinearSeq<T>
        Specified by:
        zipWithIndex in interface Seq<T>
        Specified by:
        zipWithIndex in interface Traversable<T>
        Returns:
        A new traversable containing all elements of this traversable paired with their index, starting with 0.
      • zipWithIndex

        public final <U> Stream<U> zipWithIndex​(java.util.function.BiFunction<? super T,​? super java.lang.Integer,​? extends U> mapper)
        Description copied from interface: Traversable
        Returns a traversable formed from this traversable and another Iterable collection by mapping elements. If one of the two iterables is longer than the other, its remaining elements are ignored.

        The length of the returned traversable is the minimum of the lengths of this traversable and that iterable.

        Specified by:
        zipWithIndex in interface LinearSeq<T>
        Specified by:
        zipWithIndex in interface Seq<T>
        Specified by:
        zipWithIndex in interface Traversable<T>
        Type Parameters:
        U - The type of the mapped elements.
        Parameters:
        mapper - a mapper.
        Returns:
        a new traversable containing mapped elements of this traversable and that iterable.
      • extend

        public final Stream<T> extend​(T next)
        Extends (continues) this Stream with a constantly repeated value.
        Parameters:
        next - value with which the stream should be extended
        Returns:
        new Stream composed from this stream extended with a Stream of provided value
      • extend

        public final Stream<T> extend​(java.util.function.Supplier<? extends T> nextSupplier)
        Extends (continues) this Stream with values provided by a Supplier
        Parameters:
        nextSupplier - a supplier which will provide values for extending a stream
        Returns:
        new Stream composed from this stream extended with values provided by the supplier
      • extend

        public final 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.
        Parameters:
        nextFunction - a function which calculates the next value basing on the previous value
        Returns:
        new Stream composed from this stream extended with values calculated by the provided function