IntPipelineError in a nested loop

[Paul Sandoz]

Hi Jose,

You are consuming "sy" more than once. A stream is a "traversable once" thing, just like an iterator.

In your example you need to pass in "sy" as a supplier:

   static void fold(IntStream sx, Supplier<IntStream> ssy, IntBiConsumer bc) {
       sx.forEach(nx -> ssy.get().forEach(ny -> bc.accept(nx, ny)));
   }

   class Demo {
       public static void main(String[] args) {
           IntStream sx = Streams.intRange(0, 10);
           Supplier<IntStream> ssy = () -> Streams.intRange(0, 5);
           IntBiConsumer bc = (x, y) -> System.out.println("x: " + x + ", y: " + y);
           fold(sx, ssy, bc);
       }
   }

Note your fold behaves more like a flatMap.

Paul.

On Apr 9, 2013, at 11:21 AM, Jose <jgetino at telefonica.net> wrote:
> 
> 
> Sorry if this issue has been commented before, but I coudn't find it in the
> archives.
> 
> Tryng to use IntStream to emulate a nested loop, I get a IntPipelineError.
> 
> The code is below:
> 
> public interface IntBiConsumer {
>    void accept(int n, int m);
> 
>    static void fold(IntStream sx, IntStream sy, IntBiConsumer bc) {
>        sx.forEach(nx -> sy.forEach(ny -> bc.accept(nx, ny)));
>    }
> 
>    class Demo {
>        public static void main(String[] args) {
>            IntStream sx = Streams.intRange(0, 10);
>            IntStream sy = Streams.intRange(0, 5);
>            IntBiConsumer bc = (x, y) -> System.out.println("x: " + x + ",
> y: " + y);
>            fold(sx, sy, bc);
>        }
>    }
> }	
> 
>