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 * 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.

 *

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package java.util.stream;

import java.util.Iterator;

import java.util.Spliterator;

/**

 * Base interface for stream types such as {@link Stream}, {@link IntStream},

 * etc.  Contains methods common to all stream types.

 *

 * @param <T> type of stream elements

 * @param <S> type of stream implementing {@code BaseStream}

 * @since 1.8

 */

public interface BaseStream<T, S extends BaseStream<T, S>> {

    /**

     * Returns an iterator for the elements of this stream.

     *

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

     * operation</a>.

     *

     * @return the element iterator for this stream

     */

    Iterator<T> iterator();

    /**

     * Returns a spliterator for the elements of this stream.

     *

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

     * operation</a>.

     *

     * @return the element spliterator for this stream

     */

    Spliterator<T> spliterator();

    /**

     * Returns whether this stream, when executed, would execute in parallel

     * (assuming no further modification of the stream, such as appending

     * further intermediate operations or changing its parallelism).  Calling

     * this method after invoking an intermediate or terminal stream operation

     * method may yield unpredictable results.

     *

     * @return {@code true} if this stream would execute in parallel if executed

     * without further modification otherwise {@code false}

     */

    boolean isParallel();

    /**

     * Returns an equivalent stream that is sequential.  May return

     * itself, either because the stream was already sequential, or because

     * the underlying stream state was modified to be sequential.

     *

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

     * operation</a>.

     *

     * @return a sequential stream

     */

    S sequential();

    /**

     * Returns an equivalent stream that is parallel.  May return

     * itself, either because the stream was already parallel, or because

     * the underlying stream state was modified to be parallel.

     *

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

     * operation</a>.

     *

     * @return a parallel stream

     */

    S parallel();

    /**

     * Returns an equivalent stream that is

     * <a href="package-summary.html#Ordering">unordered</a>.  May return

     * itself if the stream was already unordered.

     *

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

     * operation</a>.

     *

     * @return an unordered stream

     */

    S unordered();

}