Java Stream Operation reverse(Stream stream)

Description

reverse

License

Open Source License

Parameter

Parameter	Description
stream	an ordered stream
T	the type of the stream elements

Return

a new stream over the elements contained in the given stream in reverse order

Declaration

public static <T> Stream<T> reverse(Stream<? extends T> stream) 

Method Source Code

//package com.java2s;
/*/* w ww. ja va  2  s .  com*/
 * Copyright (C) 2018 Scientific Analysis Instruments Limited <contact@saiman.co.uk>
 *          ______         ___      ___________
 *       ,'========\     ,'===\    /========== \
 *      /== \___/== \  ,'==.== \   \__/== \___\/
 *     /==_/____\__\/,'==__|== |     /==  /
 *     \========`. ,'========= |    /==  /
 *   ___`-___)== ,'== \____|== |   /==  /
 *  /== \__.-==,'==  ,'    |== '__/==  /_
 *  \======== /==  ,'      |== ========= \
 *   \_____\.-\__\/        \__\\________\/
 *
 * This file is part of uk.co.saiman.collections.
 *
 * uk.co.saiman.collections is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * uk.co.saiman.collections 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.util.Iterator;

import java.util.List;

import java.util.Spliterator;
import java.util.Spliterators;

import java.util.stream.Collectors;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

public class Main {
    /**
     * @param stream
     *          an ordered stream
     * @param <T>
     *          the type of the stream elements
     * @return a new stream over the elements contained in the given stream in
     *         reverse order
     */
    public static <T> Stream<T> reverse(Stream<? extends T> stream) {
        List<T> collection = stream.collect(Collectors.toList());

        Iterator<T> iterator = new Iterator<T>() {
            private int index = collection.size();

            @Override
            public boolean hasNext() {
                return index > 0;
            }

            @Override
            public T next() {
                return collection.get(--index);
            }
        };

        return StreamSupport.stream(
                Spliterators.spliterator(iterator, collection.size(), Spliterator.ORDERED | Spliterator.IMMUTABLE),
                false);
    }
}

Related

1. rangeStream(int n, boolean parallel)
2. readStream(Stream s, boolean lowercase)
3. rebuildParallel(Stream stream)
4. replacePos(StringBuilder original, char replacementChar, Stream positionsToReplace)
5. replaceStr(StringBuilder original, char replacementChar, Stream stringsToReplace)
6. reverse(Stream input)
7. startsWith(Stream stream, Iterable iterable)
8. startsWith(Stream stream, Stream stream2)
9. stringPositions(StringBuilder toTest, Stream strings)