Early/late binding to data source

[Remi Forax]

On 11/29/2012 05:29 PM, Brian Goetz wrote:
> We've already committed to a model where stream operations do not 
> tolerate modification of their data source during the operation. For 
> example, this is illegal:
>
>   collection.stream().forEach(e -> collection.removeAll(e));

by illegal, it hopes it means it should throw a 
ConcurrentModificationException and not the result is random, good luck.

>
> We've also tightened down the spec on "source sharing" and "stream 
> reuse".
>
> We now have to define what "during" means.  We make a substantial 
> effort to not touch the data until the user wants to do something with 
> it.  So, what should happen in this case:
>
>   List<String> strings = new ArrayList<>(Arrays.asList("a"));
>   Stream<String> s = strings.stream();
>   strings.clear();
>   s.forEach(System.out::println);
>
>

It should print nothing, creating a stream, filter it etc. are lazy 
operations, only terminal ops do something.

Rémi