How to interleave (merge) two Java 8 Streams?

Question

 Stream a = Stream.of(\"one\", \"three\", \"five\");
 Stream b = Stream.of(\"two\", \"four\", \"six\");

What do I need

Answer 1

As you can see from the question comments, I gave this a go using zip:

Stream a = Stream.of("one", "three", "five");
Stream b = Stream.of("two", "four", "six");

Stream out = interleave(a, b);


    public static  Stream interleave(Stream streamA, Stream streamB) {
        return zip(streamA, streamB, (o1, o2) -> Stream.of(o1, o2)).flatMap(s -> s);
    }

    /**
    * https://stackoverflow.com/questions/17640754/zipping-streams-using-jdk8-with-lambda-java-util-stream-streams-zip
    **/
    private static  Stream zip(Stream streamA, Stream streamB, BiFunction zipper) {
        final Iterator iteratorA = streamA.iterator();
        final Iterator iteratorB = streamB.iterator();
        final Iterator iteratorC = new Iterator() {
            @Override
            public boolean hasNext() {
                return iteratorA.hasNext() && iteratorB.hasNext();
            }

            @Override
            public C next() {
                return zipper.apply(iteratorA.next(), iteratorB.next());
            }
        };
        final boolean parallel = streamA.isParallel() || streamB.isParallel();
        return iteratorToFiniteStream(iteratorC, parallel);
    }

    private static  Stream iteratorToFiniteStream(Iterator iterator, boolean parallel) {
        final Iterable iterable = () -> iterator;
        return StreamSupport.stream(iterable.spliterator(), parallel);
    }