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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

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 *

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package java.util.stream;

import java.util.Arrays;

import java.util.LongSummaryStatistics;

import java.util.Objects;

import java.util.OptionalDouble;

import java.util.OptionalLong;

import java.util.PrimitiveIterator;

import java.util.Spliterator;

import java.util.Spliterators;

import java.util.function.BiConsumer;

import java.util.function.Function;

import java.util.function.LongBinaryOperator;

import java.util.function.LongConsumer;

import java.util.function.LongFunction;

import java.util.function.LongPredicate;

import java.util.function.LongSupplier;

import java.util.function.LongToDoubleFunction;

import java.util.function.LongToIntFunction;

import java.util.function.LongUnaryOperator;

import java.util.function.ObjLongConsumer;

import java.util.function.Supplier;

/**

 *

 *

 *

 *

 *

 * @since 1.8

 * @see <a href="package-summary.html">java.util.stream</a>

 */

public interface LongStream extends BaseStream<Long, LongStream> {

    /**

     * Returns a stream consisting of the elements of this stream that match

     * the given predicate.

     *

     * <p>This is an <a href="package-summary.html#StreamOps">intermediate

     * operation</a>.

     *

     * @param predicate a <a href="package-summary.html#NonInterference">

     *                  non-interfering, stateless</a> predicate to apply to

     *                  each element to determine if it should be included

     * @return the new stream

     */

    LongStream filter(LongPredicate predicate);

    /**

     * Returns a stream consisting of the results of applying the given

     * function to the elements of this stream.

     *

     * <p>This is an <a href="package-summary.html#StreamOps">intermediate

     * operation</a>.

     *

     * @param mapper a <a href="package-summary.html#NonInterference">

     *               non-interfering, stateless</a> function to apply to each

     *               element

     * @return the new stream

     */

    LongStream map(LongUnaryOperator mapper);

    /**

     * Returns an object-valued {@code Stream} consisting of the results of

     * applying the given function to the elements of this stream.

     *

     * <p>This is an <a href="package-summary.html#StreamOps">

     *     intermediate operation</a>.

     *

     * @param <U> the element type of the new stream

     * @param mapper a <a href="package-summary.html#NonInterference">

     *               non-interfering, stateless</a> function to apply to each

     *               element

     * @return the new stream

     */

    <U> Stream<U> mapToObj(LongFunction<? extends U> mapper);

    /**

     * Returns an {@code IntStream} consisting of the results of applying the

     * given function to the elements of this stream.

     *

     * <p>This is an <a href="package-summary.html#StreamOps">intermediate

     * operation</a>.

     *

     * @param mapper a <a href="package-summary.html#NonInterference">

     *               non-interfering, stateless</a> function to apply to each

     *               element

     * @return the new stream

     */

    IntStream mapToInt(LongToIntFunction mapper);

    /**

     * Returns a {@code DoubleStream} consisting of the results of applying the

     * given function to the elements of this stream.

     *

     * <p>This is an <a href="package-summary.html#StreamOps">intermediate

     * operation</a>.

     *

     * @param mapper a <a href="package-summary.html#NonInterference">

     *               non-interfering, stateless</a> function to apply to each

     *               element

     * @return the new stream

     */

    DoubleStream mapToDouble(LongToDoubleFunction mapper);

    /**

     * Returns a stream consisting of the results of replacing each element of

     * this stream with the contents of the stream produced by applying the

     *

     * <p>This is an <a href="package-summary.html#StreamOps">intermediate

     * operation</a>.

     *

     * @param mapper a <a href="package-summary.html#NonInterference">

     *               non-interfering, stateless</a> function to apply to

     *               each element which produces an {@code LongStream} of new

     *               values

     * @return the new stream

     * @see Stream#flatMap(Function)

     */

    LongStream flatMap(LongFunction<? extends LongStream> mapper);

    /**

     * Returns a stream consisting of the distinct elements of this stream.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">stateful

     * intermediate operation</a>.

     *

     * @return the new stream

     */

    LongStream distinct();

    /**

     * Returns a stream consisting of the elements of this stream in sorted

     * order.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">stateful

     * intermediate operation</a>.

     *

     * @return the new stream

     */

    LongStream sorted();

    /**

     * Returns a stream consisting of the elements of this stream, additionally

     * performing the provided action on each element as elements are consumed

     * from the resulting stream.

     *

     * <p>This is an <a href="package-summary.html#StreamOps">intermediate

     * operation</a>.

     *

     * <p>For parallel stream pipelines, the action may be called at

     * whatever time and in whatever thread the element is made available by the

     * upstream operation.  If the action modifies shared state,

     * it is responsible for providing the required synchronization.

     *

     * @apiNote This method exists mainly to support debugging, where you want

     * to see the elements as they flow past a certain point in a pipeline:

     * <pre>{@code

     *     list.stream()

     *         .filter(filteringFunction)

     *         .map(mappingFunction)

     *         .collect(Collectors.toLongSummaryStastistics());

     * }</pre>

     *

     * @return the new stream

     */

    /**

     * Returns a stream consisting of the elements of this stream, truncated

     * to be no longer than {@code maxSize} in length.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">short-circuiting

     * stateful intermediate operation</a>.

     *

     * @param maxSize the number of elements the stream should be limited to

     * @return the new stream

     * @throws IllegalArgumentException if {@code maxSize} is negative

     */

    LongStream limit(long maxSize);

    /**

     * Returns a stream consisting of the remaining elements of this stream

     * empty stream will be returned.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">stateful

     * intermediate operation</a>.

     *

     * @param startInclusive the number of leading elements to skip

     * @return the new stream

     * @throws IllegalArgumentException if {@code startInclusive} is negative

     */

    LongStream substream(long startInclusive);

    /**

     * Returns a stream consisting of the remaining elements of this stream

     *

     * <p>This is a <a href="package-summary.html#StreamOps">short-circuiting

     * stateful intermediate operation</a>.

     *

     * @param startInclusive the starting position of the substream, inclusive

     * @param endExclusive the ending position of the substream, exclusive

     * @return the new stream

     * @throws IllegalArgumentException if {@code startInclusive} or

     * {@code endExclusive} is negative or {@code startInclusive} is greater

     * than {@code endExclusive}

     */

    LongStream substream(long startInclusive, long endExclusive);

    /**

     * Performs an action for each element of this stream.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">terminal

     * operation</a>.

     *

     * <p>For parallel stream pipelines, this operation does <em>not</em>

     * guarantee to respect the encounter order of the stream, as doing so

     * would sacrifice the benefit of parallelism.  For any given element, the

     * action may be performed at whatever time and in whatever thread the

     * library chooses.  If the action accesses shared state, it is

     * responsible for providing the required synchronization.

     *

     * @param action a <a href="package-summary.html#NonInterference">

     *               non-interfering</a> action to perform on the elements

     */

    void forEach(LongConsumer action);

    /**

     * Performs an action for each element of this stream, guaranteeing that

     * each element is processed in encounter order for streams that have a

     * defined encounter order.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">terminal

     * operation</a>.

     *

     * @param action a <a href="package-summary.html#NonInterference">

     *               non-interfering</a> action to perform on the elements

     * @see #forEach(LongConsumer)

     */

    void forEachOrdered(LongConsumer action);

    /**

     * Returns an array containing the elements of this stream.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">terminal

     * operation</a>.

     *

     * @return an array containing the elements of this stream

     */

    long[] toArray();

    /**

     * Performs a <a href="package-summary.html#Reduction">reduction</a> on the

     * elements of this stream, using the provided identity value and an

     * <a href="package-summary.html#Associativity">associative</a>

     * accumulation function, and returns the reduced value.  This is equivalent

     * to:

     * <pre>{@code

     *     long result = identity;

     *     for (long element : this stream)

     *         result = accumulator.apply(result, element)

     *     return result;

     * }</pre>

     *

     * but is not constrained to execute sequentially.

     *

     * <p>The {@code identity} value must be an identity for the accumulator

     * function. This means that for all {@code x},

     * {@code accumulator.apply(identity, x)} is equal to {@code x}.

     * The {@code accumulator} function must be an

     * <a href="package-summary.html#Associativity">associative</a> function.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">terminal

     * operation</a>.

     *

     * @apiNote Sum, min, max, and average are all special cases of reduction.

     * Summing a stream of numbers can be expressed as:

     *

     * <pre>{@code

     *     long sum = integers.reduce(0, (a, b) -> a+b);

     * }</pre>

     *

     * or more compactly:

     *

     * <pre>{@code

     *     long sum = integers.reduce(0, Long::sum);

     * }</pre>

     *

     * <p>While this may seem a more roundabout way to perform an aggregation

     * compared to simply mutating a running total in a loop, reduction

     * operations parallelize more gracefully, without needing additional

     * synchronization and with greatly reduced risk of data races.

     *

     * @param identity the identity value for the accumulating function

     * @param op an <a href="package-summary.html#Associativity">associative</a>

     *                    <a href="package-summary.html#NonInterference">non-interfering,

     *                    stateless</a> function for combining two values

     * @return the result of the reduction

     * @see #sum()

     * @see #min()

     * @see #max()

     * @see #average()

     */

    long reduce(long identity, LongBinaryOperator op);

    /**

     * Performs a <a href="package-summary.html#Reduction">reduction</a> on the

     * elements of this stream, using an

     * <a href="package-summary.html#Associativity">associative</a> accumulation

     * function, and returns an {@code OptionalLong} describing the reduced value,

     * if any. This is equivalent to:

     * <pre>{@code

     *     boolean foundAny = false;

     *     long result = null;

     *     for (long element : this stream) {

     *         if (!foundAny) {

     *             foundAny = true;

     *             result = element;

     *         }

     *         else

     *             result = accumulator.apply(result, element);

     *     }

     *     return foundAny ? OptionalLong.of(result) : OptionalLong.empty();

     * }</pre>

     *

     * but is not constrained to execute sequentially.

     *

     * <p>The {@code accumulator} function must be an

     * <a href="package-summary.html#Associativity">associative</a> function.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">terminal

     * operation</a>.

     *

     * @param op an <a href="package-summary.html#Associativity">associative</a>

     *           <a href="package-summary.html#NonInterference">non-interfering,

     *           stateless</a> function for combining two values

     * @return the result of the reduction

     * @see #reduce(long, LongBinaryOperator)

     */

    OptionalLong reduce(LongBinaryOperator op);

    /**

     * Performs a <a href="package-summary.html#MutableReduction">mutable

     * reduction</a> operation on the elements of this stream.  A mutable

     * such as an {@code ArrayList}, and elements are incorporated by updating

     * produces a result equivalent to:

     * <pre>{@code

     *     for (long element : this stream)

     *         accumulator.accept(result, element);

     *     return result;

     * }</pre>

     *

     * <p>Like {@link #reduce(long, LongBinaryOperator)}, {@code collect} operations

     * can be parallelized without requiring additional synchronization.

     *

     * <p>This is a <a href="package-summary.html#StreamOps">terminal

     * operation</a>.

     *

     * @param <R> type of the result

     * @param accumulator an <a href="package-summary.html#Associativity">associative</a>

     *                    <a href="package-summary.html#NonInterference">non-interfering,

     *                    stateless</a> function for incorporating an additional

     *                    element into a result

     * @param combiner an <a href="package-summary.html#Associativity">associative</a>

     *                 <a href="package-summary.html#NonInterference">non-interfering,

     *                 stateless</a> function for combining two values, which

     *                 must be compatible with the accumulator function

     * @return the result of the reduction

     * @see Stream#collect(Supplier, BiConsumer, BiConsumer)

     */

                  ObjLongConsumer<R> accumulator,

                  BiConsumer<R, R> combiner);

    /**

     * Returns the sum of elements in this stream.  This is a special case

     * and is equivalent to:

     * <pre>{@code

     *     return reduce(0, Long::sum);

     * }</pre>

     *

     * @return the sum of elements in this stream

     */

    long sum();

    /**

     * Returns an {@code OptionalLong} describing the minimum element of this

     * stream, or an empty optional if this stream is empty.  This is a special