/*
 * Copyright (c) 2012, 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.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.
 * @since 1.8
 */
interface BaseStream<T, S extends BaseStream<T, S>> {
    /**
     * Return an iterator for the elements of this stream.  This is
     * a <a href="package-summary.html#StreamOps">terminal operation</a>.
     *
     * @return the element iterator for this stream
     */
    Iterator<T> iterator();

    /**
     * Return a spliterator for the elements of this stream.  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, will execute in parallel
     *
     * @return whether this stream will execute in parallel
     */
    boolean isParallel();

    /**
     * Return the composition of stream flags of the stream source and all intermediate operations.
     *
     * @return the composition of stream flags of the stream source and all intermediate operations
     * @see StreamOpFlag
     */
    int getStreamFlags();

    /**
     * Produce a stream which has the same contents as this stream, but is a sequential stream.  If this stream is
     * already sequential, may return itself.  This is
     * a <a href="package-summary.html#StreamOps">stateful intermediate operation</a>.
     *
     * @return a sequential stream
     */
    S sequential();

    /**
     * Produce a stream which has the same contents as this stream, but is a parallel stream.  If this stream is
     * already parallel, may return itself.  This is
     * a <a href="package-summary.html#StreamOps">stateful intermediate operation</a>.
     *
     * @return a parallel stream
     */
    S parallel();
}