Inconsistent interfaces between 'Paged' classes

[SergiusAC]

Issue #1538 says next:

cactoos/src/main/java/org/cactoos/iterable/Paged.java

Lines 38 to 42 in 86ad37b

	* @todo #1464:30min Replace the constructor so that instead it takes a {@link Iterable}
	* as first and a {@code Func<Iterable, Iterable>} as next in order to homogenise it with
	* the other {@link Iterable} implementations.
	*/
	public final class Paged<X> extends IterableEnvelope<X> {

But this replacing is inconsistent with the interface in the next class:

cactoos/src/main/java/org/cactoos/iterator/Paged.java

Lines 42 to 67 in 86ad37b

	* @todo #1464:30min We want to use {@code Iterator<X>} directly in the class without
	* introducing I, maybe using {@code Iterator<? extends X>} for example because, we don't
	* have to constrain the {@link Func} to give exactly the same Iterator type as long as it
	* is an iterator that provides X. {@link org.cactoos.iterable.Paged} should be changed too.
	*/
	public final class Paged<I extends Iterator<X>, X> implements Iterator<X> {
	/**
	* Current element.
	*/
	private final AtomicReference<I> current;
	/**
	* Function to get the next element.
	*/
	private final Func<I, I> subsequent;
	/**
	* Ctor.
	* @param first First element.
	* @param next Function to get the next element.
	*/
	public Paged(final I first, final Func<I, I> next) {
	this.current = new AtomicReference<>(first);
	this.subsequent = next;
	}

This inconsistency prevents issues #1538 and #1537 from being completed.

[victornoel]

@SergiusAC I don't understand what exactly is the problem. The two todos seem to be two orthogonal concerns. The first one is about parameter order in the constructor and the second one is about removing a useless type parameter (generic) of the class.

[SergiusAC]

@victornoel the iterable.Paged constructor should take the parameter 'next' as 'Func<Iterable, Iterable>', it is mentioned in first todo. But the iterator.Paged constructor takes the corresponding parameter as 'Func<Iterator, Iterator>'. So we cannot invoke the iterator.Paged constructor and pass it the parameter 'next'.

[victornoel]

@SergiusAC well, this is the purpose of the task to find a solution. I see you refused the task, so maybe let it for the next person it will be assigned to. I don't see any problem with it, most of the Iterable of Cactoos are implemented by delegating to the corresponding Iterator implementation, so it should be doable. I don't have the solution exactly, but if I had, I would have done the job.

If I understand well, it seems your question is about #1537, not about #1538 (which is just about switching two parameters in a constructor…), so I think next time, you can directly discuss it in the ticket of the problematic case :)

[victornoel]

@SergiusAC oh wait, I'm mistaken, the question is indeed about #1538, sorry. Anyway, my answer stands, we should find a way to take an iterable instead of an iterator in iterable.Paged.

[victornoel]

@SergiusAC re-reading my answers, maybe something is not clear:

• the objective of Paged.java:38-40: Replace the constructor so that instead... #1538 is to have the constructor of iterable.Paged take a Func<Iterable, Iterable> but invoke iterator.Paged with a Func<Iterator, Iterator>, like it is done in all the other Iterable implementations of Cactoos. The solution is not obvious but there is not reason not to be possible, most certainly using func.Mapped or something like that.
• the objective of Paged.java:42-45: We want to use {@code Iterator<X>}... #1537 is to simplify the implementation of the class of iterator.Paged but still passing a Func<Iterator, Iterator> to the constructor

I believe your question was thus about #1538. I propose that if all is clear to you, we close this ticket and I will add a link to this discussion in #1538 for the next person to tackle it :) or if you want to tackle it I can re-assign it to you with no problem :)

[SergiusAC]

@victornoel I think this ticket can be closed, because solution to make interfaces between the classes consistent can be done like this

new org.cactoos.iterator.Paged<X>(
    first.iterator(),
    page -> next.apply(new IterableOf<>(page)).iterator()
)

Also, if it is possible, then re-assign #1538 to me again, please.

[victornoel]

@SergiusAC exactly, good solution

[0crat]

Job gh:yegor256/cactoos#1595 is not assigned, can't get performer