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	/*
	* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/
	package java.util.stream;

	import java.util.Objects;
	import java.util.Spliterator;
	import java.util.function.Supplier;

	/**
	* Low-level utility methods for creating and manipulating streams.
	*
	* <p>This class is mostly for library writers presenting stream views
	* of data structures; most static stream methods intended for end users are in
	* the various {@code Stream} classes.
	*
	* @since 1.8
	*/
	public final class StreamSupport {

	// Suppresses default constructor, ensuring non-instantiability.
	private StreamSupport() {}

	/**
	* Creates a new sequential or parallel {@code Stream} from a
	* {@code Spliterator}.
	*
	* <p>The spliterator is only traversed, split, or queried for estimated
	* size after the terminal operation of the stream pipeline commences.
	*
	* <p>It is strongly recommended the spliterator report a characteristic of
	* {@code IMMUTABLE} or {@code CONCURRENT}, or be
	* <a href="../Spliterator.html#binding">late-binding</a>. Otherwise,
	* {@link #stream(java.util.function.Supplier, int, boolean)} should be used
	* to reduce the scope of potential interference with the source. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param <T> the type of stream elements
	* @param spliterator a {@code Spliterator} describing the stream elements
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code Stream}
	*/
	public static <T> Stream<T> stream(Spliterator<T> spliterator, boolean parallel) {
	Objects.requireNonNull(spliterator);
	return new ReferencePipeline.Head<>(spliterator,
	StreamOpFlag.fromCharacteristics(spliterator),
	parallel);
	}

	/**
	* Creates a new sequential or parallel {@code Stream} from a
	* {@code Supplier} of {@code Spliterator}.
	*
	* <p>The {@link Supplier#get()} method will be invoked on the supplier no
	* more than once, and only after the terminal operation of the stream pipeline
	* commences.
	*
	* <p>For spliterators that report a characteristic of {@code IMMUTABLE}
	* or {@code CONCURRENT}, or that are
	* <a href="../Spliterator.html#binding">late-binding</a>, it is likely
	* more efficient to use {@link #stream(java.util.Spliterator, boolean)}
	* instead.
	* <p>The use of a {@code Supplier} 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. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param <T> the type of stream elements
	* @param supplier a {@code Supplier} of a {@code Spliterator}
	* @param characteristics Spliterator characteristics of the supplied
	* {@code Spliterator}. The characteristics must be equal to
	* {@code supplier.get().characteristics()}, otherwise undefined
	* behavior may occur when terminal operation commences.
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code Stream}
	* @see #stream(java.util.Spliterator, boolean)
	*/
	public static <T> Stream<T> stream(Supplier<? extends Spliterator<T>> supplier,
	int characteristics,
	boolean parallel) {
	Objects.requireNonNull(supplier);
	return new ReferencePipeline.Head<>(supplier,
	StreamOpFlag.fromCharacteristics(characteristics),
	parallel);
	}

	/**
	* Creates a new sequential or parallel {@code IntStream} from a
	* {@code Spliterator.OfInt}.
	*
	* <p>The spliterator is only traversed, split, or queried for estimated size
	* after the terminal operation of the stream pipeline commences.
	*
	* <p>It is strongly recommended the spliterator report a characteristic of
	* {@code IMMUTABLE} or {@code CONCURRENT}, or be
	* <a href="../Spliterator.html#binding">late-binding</a>. Otherwise,
	* {@link #intStream(java.util.function.Supplier, int, boolean)} should be
	* used to reduce the scope of potential interference with the source. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param spliterator a {@code Spliterator.OfInt} describing the stream elements
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code IntStream}
	*/
	public static IntStream intStream(Spliterator.OfInt spliterator, boolean parallel) {
	return new IntPipeline.Head<>(spliterator,
	StreamOpFlag.fromCharacteristics(spliterator),
	parallel);
	}

	/**
	* Creates a new sequential or parallel {@code IntStream} from a
	* {@code Supplier} of {@code Spliterator.OfInt}.
	*
	* <p>The {@link Supplier#get()} method will be invoked on the supplier no
	* more than once, and only after the terminal operation of the stream pipeline
	* commences.
	*
	* <p>For spliterators that report a characteristic of {@code IMMUTABLE}
	* or {@code CONCURRENT}, or that are
	* <a href="../Spliterator.html#binding">late-binding</a>, it is likely
	* more efficient to use {@link #intStream(java.util.Spliterator.OfInt, boolean)}
	* instead.
	* <p>The use of a {@code Supplier} 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. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param supplier a {@code Supplier} of a {@code Spliterator.OfInt}
	* @param characteristics Spliterator characteristics of the supplied
	* {@code Spliterator.OfInt}. The characteristics must be equal to
	* {@code supplier.get().characteristics()}, otherwise undefined
	* behavior may occur when terminal operation commences.
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code IntStream}
	* @see #intStream(java.util.Spliterator.OfInt, boolean)
	*/
	public static IntStream intStream(Supplier<? extends Spliterator.OfInt> supplier,
	int characteristics,
	boolean parallel) {
	return new IntPipeline.Head<>(supplier,
	StreamOpFlag.fromCharacteristics(characteristics),
	parallel);
	}

	/**
	* Creates a new sequential or parallel {@code LongStream} from a
	* {@code Spliterator.OfLong}.
	*
	* <p>The spliterator is only traversed, split, or queried for estimated
	* size after the terminal operation of the stream pipeline commences.
	*
	* <p>It is strongly recommended the spliterator report a characteristic of
	* {@code IMMUTABLE} or {@code CONCURRENT}, or be
	* <a href="../Spliterator.html#binding">late-binding</a>. Otherwise,
	* {@link #longStream(java.util.function.Supplier, int, boolean)} should be
	* used to reduce the scope of potential interference with the source. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param spliterator a {@code Spliterator.OfLong} describing the stream elements
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code LongStream}
	*/
	public static LongStream longStream(Spliterator.OfLong spliterator,
	boolean parallel) {
	return new LongPipeline.Head<>(spliterator,
	StreamOpFlag.fromCharacteristics(spliterator),
	parallel);
	}

	/**
	* Creates a new sequential or parallel {@code LongStream} from a
	* {@code Supplier} of {@code Spliterator.OfLong}.
	*
	* <p>The {@link Supplier#get()} method will be invoked on the supplier no
	* more than once, and only after the terminal operation of the stream pipeline
	* commences.
	*
	* <p>For spliterators that report a characteristic of {@code IMMUTABLE}
	* or {@code CONCURRENT}, or that are
	* <a href="../Spliterator.html#binding">late-binding</a>, it is likely
	* more efficient to use {@link #longStream(java.util.Spliterator.OfLong, boolean)}
	* instead.
	* <p>The use of a {@code Supplier} 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. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param supplier a {@code Supplier} of a {@code Spliterator.OfLong}
	* @param characteristics Spliterator characteristics of the supplied
	* {@code Spliterator.OfLong}. The characteristics must be equal to
	* {@code supplier.get().characteristics()}, otherwise undefined
	* behavior may occur when terminal operation commences.
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code LongStream}
	* @see #longStream(java.util.Spliterator.OfLong, boolean)
	*/
	public static LongStream longStream(Supplier<? extends Spliterator.OfLong> supplier,
	int characteristics,
	boolean parallel) {
	return new LongPipeline.Head<>(supplier,
	StreamOpFlag.fromCharacteristics(characteristics),
	parallel);
	}

	/**
	* Creates a new sequential or parallel {@code DoubleStream} from a
	* {@code Spliterator.OfDouble}.
	*
	* <p>The spliterator is only traversed, split, or queried for estimated size
	* after the terminal operation of the stream pipeline commences.
	*
	* <p>It is strongly recommended the spliterator report a characteristic of
	* {@code IMMUTABLE} or {@code CONCURRENT}, or be
	* <a href="../Spliterator.html#binding">late-binding</a>. Otherwise,
	* {@link #doubleStream(java.util.function.Supplier, int, boolean)} should
	* be used to reduce the scope of potential interference with the source. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param spliterator A {@code Spliterator.OfDouble} describing the stream elements
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code DoubleStream}
	*/
	public static DoubleStream doubleStream(Spliterator.OfDouble spliterator,
	boolean parallel) {
	return new DoublePipeline.Head<>(spliterator,
	StreamOpFlag.fromCharacteristics(spliterator),
	parallel);
	}

	/**
	* Creates a new sequential or parallel {@code DoubleStream} from a
	* {@code Supplier} of {@code Spliterator.OfDouble}.
	*
	* <p>The {@link Supplier#get()} method will be invoked on the supplier no
	* more than once, and only after the terminal operation of the stream pipeline
	* commences.
	*
	* <p>For spliterators that report a characteristic of {@code IMMUTABLE}
	* or {@code CONCURRENT}, or that are
	* <a href="../Spliterator.html#binding">late-binding</a>, it is likely
	* more efficient to use {@link #doubleStream(java.util.Spliterator.OfDouble, boolean)}
	* instead.
	* <p>The use of a {@code Supplier} 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. See
	* <a href="package-summary.html#NonInterference">Non-Interference</a> for
	* more details.
	*
	* @param supplier A {@code Supplier} of a {@code Spliterator.OfDouble}
	* @param characteristics Spliterator characteristics of the supplied
	* {@code Spliterator.OfDouble}. The characteristics must be equal to
	* {@code supplier.get().characteristics()}, otherwise undefined
	* behavior may occur when terminal operation commences.
	* @param parallel if {@code true} then the returned stream is a parallel
	* stream; if {@code false} the returned stream is a sequential
	* stream.
	* @return a new sequential or parallel {@code DoubleStream}
	* @see #doubleStream(java.util.Spliterator.OfDouble, boolean)
	*/
	public static DoubleStream doubleStream(Supplier<? extends Spliterator.OfDouble> supplier,
	int characteristics,
	boolean parallel) {
	return new DoublePipeline.Head<>(supplier,
	StreamOpFlag.fromCharacteristics(characteristics),
	parallel);
	}
	}

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