Module java.base
Package java.util.stream

Class StreamSupport

  • public final classStreamSupportextendsObject
    Low-level utility methods for creating and manipulating streams.

    This class is mostly for library writers presenting stream views of data structures; most static stream methods intended for end users are in the variousStream classes.

    Since:
    1.8

    • Method Detail

      • stream

        public static <T> Stream<T> stream​(Spliterator<T> spliterator,                                   boolean parallel)
        Creates a new sequential or parallelStream from aSpliterator.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic ofIMMUTABLE orCONCURRENT, or belate-binding. Otherwise,stream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. SeeNon-Interference for more details.

        Type Parameters:
        T - the type of stream elements
        Parameters:
        spliterator - aSpliterator describing the stream elements
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelStream

      • stream

        public static <T> Stream<T> stream​(Supplier<? extendsSpliterator<T>> supplier,                                   int characteristics,                                   boolean parallel)
        Creates a new sequential or parallelStream from aSupplier ofSpliterator.

        TheSupplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic ofIMMUTABLE orCONCURRENT, or that arelate-binding, it is likely more efficient to usestream(java.util.Spliterator, boolean) instead.

        The use of aSupplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. SeeNon-Interference for more details.

        Type Parameters:
        T - the type of stream elements
        Parameters:
        supplier - aSupplier of aSpliterator
        characteristics - Spliterator characteristics of the suppliedSpliterator. The characteristics must be equal tosupplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelStream
        See Also:
        stream(java.util.Spliterator, boolean)

      • intStream

        public static IntStream intStream​(Spliterator.OfInt spliterator,                                  boolean parallel)
        Creates a new sequential or parallelIntStream from aSpliterator.OfInt.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic ofIMMUTABLE orCONCURRENT, or belate-binding. Otherwise,intStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. SeeNon-Interference for more details.

        Parameters:
        spliterator - aSpliterator.OfInt describing the stream elements
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelIntStream

      • intStream

        public static IntStream intStream​(Supplier<? extendsSpliterator.OfInt> supplier,                                  int characteristics,                                  boolean parallel)
        Creates a new sequential or parallelIntStream from aSupplier ofSpliterator.OfInt.

        TheSupplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic ofIMMUTABLE orCONCURRENT, or that arelate-binding, it is likely more efficient to useintStream(java.util.Spliterator.OfInt, boolean) instead.

        The use of aSupplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. SeeNon-Interference for more details.

        Parameters:
        supplier - aSupplier of aSpliterator.OfInt
        characteristics - Spliterator characteristics of the suppliedSpliterator.OfInt. The characteristics must be equal tosupplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelIntStream
        See Also:
        intStream(java.util.Spliterator.OfInt, boolean)

      • longStream

        public static LongStream longStream​(Spliterator.OfLong spliterator,                                    boolean parallel)
        Creates a new sequential or parallelLongStream from aSpliterator.OfLong.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic ofIMMUTABLE orCONCURRENT, or belate-binding. Otherwise,longStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. SeeNon-Interference for more details.

        Parameters:
        spliterator - aSpliterator.OfLong describing the stream elements
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelLongStream

      • longStream

        public static LongStream longStream​(Supplier<? extendsSpliterator.OfLong> supplier,                                    int characteristics,                                    boolean parallel)
        Creates a new sequential or parallelLongStream from aSupplier ofSpliterator.OfLong.

        TheSupplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic ofIMMUTABLE orCONCURRENT, or that arelate-binding, it is likely more efficient to uselongStream(java.util.Spliterator.OfLong, boolean) instead.

        The use of aSupplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. SeeNon-Interference for more details.

        Parameters:
        supplier - aSupplier of aSpliterator.OfLong
        characteristics - Spliterator characteristics of the suppliedSpliterator.OfLong. The characteristics must be equal tosupplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelLongStream
        See Also:
        longStream(java.util.Spliterator.OfLong, boolean)

      • doubleStream

        public static DoubleStream doubleStream​(Spliterator.OfDouble spliterator,                                        boolean parallel)
        Creates a new sequential or parallelDoubleStream from aSpliterator.OfDouble.

        The spliterator is only traversed, split, or queried for estimated size after the terminal operation of the stream pipeline commences.

        It is strongly recommended the spliterator report a characteristic ofIMMUTABLE orCONCURRENT, or belate-binding. Otherwise,doubleStream(java.util.function.Supplier, int, boolean) should be used to reduce the scope of potential interference with the source. SeeNon-Interference for more details.

        Parameters:
        spliterator - ASpliterator.OfDouble describing the stream elements
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelDoubleStream

      • doubleStream

        public static DoubleStream doubleStream​(Supplier<? extendsSpliterator.OfDouble> supplier,                                        int characteristics,                                        boolean parallel)
        Creates a new sequential or parallelDoubleStream from aSupplier ofSpliterator.OfDouble.

        TheSupplier.get() method will be invoked on the supplier no more than once, and only after the terminal operation of the stream pipeline commences.

        For spliterators that report a characteristic ofIMMUTABLE orCONCURRENT, or that arelate-binding, it is likely more efficient to usedoubleStream(java.util.Spliterator.OfDouble, boolean) instead.

        The use of aSupplier in this form provides a level of indirection that reduces the scope of potential interference with the source. Since the supplier is only invoked after the terminal operation commences, any modifications to the source up to the start of the terminal operation are reflected in the stream result. SeeNon-Interference for more details.

        Parameters:
        supplier - ASupplier of aSpliterator.OfDouble
        characteristics - Spliterator characteristics of the suppliedSpliterator.OfDouble. The characteristics must be equal tosupplier.get().characteristics(), otherwise undefined behavior may occur when terminal operation commences.
        parallel - iftrue then the returned stream is a parallel stream; iffalse the returned stream is a sequential stream.
        Returns:
        a new sequential or parallelDoubleStream
        See Also:
        doubleStream(java.util.Spliterator.OfDouble, boolean)