Make @for work with any Iterable object

[bendem]

This change makes the rocker @for syntax match the java syntax by accepting any object implementing Iterable.

I've added this as a workaround for the @for syntax not working with streams (see #40) (passing stream::iterator to the template instead of collecting to a list - and thus saving my server from high memory usage), but I'm sure others will appreciate not requiring a Collection when all that's used is the Iterable interface.

[bendem]

Any news on this?

[jjlauer]

Hey @bendem, sorry for missing the original github notification about this PR. I love the idea of supporting iterable (eventually streams too). Just a few issues with this PR:

1. We need a unit test for it of something that's Iterable and not a Collection.
2. Iterable could be supported in both Java 8 and Java 6 -- but it seems like you only added support for it in Java 8. So while adding a test for 1), make sure you add it in both the java6 and java8 modules.
3. What about Rocker iterator support (https://github.com/fizzed/rocker/blob/master/docs/SYNTAX.md#iteration-for)? That's a key feature and I'm not sure how we support it with streams and/or iterables. Obviously, last is probably the only method that can't be supported on it. Ideally, the Java compiler would catch that if using an iterable -- vs. something like a runtime exception.

[bendem]

All of that makes sense, I'll try and look into it later this week.

[bendem]

I have replaced CollectionForIterator with IterableForIterator. That should cover all cases where rocker was using Collection instead of Iterable at once. I have not looked into Stream support (maybe another time).

[bendem]

Is there anything else I can do to make your review easier?

[jjlauer]

@bendem This looks good. Thanks for the contrib. Will ship it in next release.

[jjlauer]

Version 0.23.0 is released with this change. Will hit maven central in couple hours.

[bendem]

Awesome, thanks!