Stream generators (original) (raw)

Joe Bowbeer joe.bowbeer at gmail.com
Fri Nov 30 10:09:46 PST 2012

I mean a more general merge which may emit an element from either stream, depending, and may drop some elements from one or both streams. On Nov 30, 2012 9:51 AM, "Brian Goetz" <brian.goetz at oracle.com> wrote:

I think it would be beneficial for comparison to show a bit of their

implementations.

Here's iterate(seed, UnaryOperator): public static Stream iterate(final T seed, final UnaryOperator f) { Objects.requireNonNull(f); final InfiniteIterator iterator = new InfiniteIterator() { T t = null; @Override public T next() { return t = (t == null) ? seed : f.operate(t); } }; return stream(new StreamSource.ForIterator<>(**iterator), StreamOpFlag.ISORDERED); } Not too difficult. But, the idea is to make things that are easy in the header of a for-loop to be easy as the source of a stream. repeat(n) in Scheme is about 10 characters. Yeah, well this is Java... How difficult is it to implement a merge, as might be needed to generate Hamming numbers? (One of my favorite test cases.) You mean, interleave two streams? That's on our list to implement as Streams.interleave(a, b). Is there a method to limit a stream to a length? If so then one of your methods may be extra baggage. Yes: stream.limit(n).

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