Rhino shell compatibility

David P. Caldwell david at code.davidpcaldwell.com
Wed May 14 01:15:15 UTC 2014

I guess my view is that since mozilla_compat.js is intended to ease
transition, the JavaAdapter cover, for example, should also provide
the less strict form; this wouldn't harm the preferred Java.extend
target for migration, which could continue to use the stricter form.

Similarly, readFile and readUrl wouldn't be hard to implement; I
implemented each of them (poorly, but sufficiently) in perhaps 5-7
lines of code.

Maybe there are sound reasons to exclude these (particularly if there
are technical reasons I don't understand that would make the
JavaAdapter defaults difficult), but my view would be, why not provide
the smoothest possible glide path when providing a compatibility layer
that is explicitly for that purpose?

-- David P. Caldwell

On Mon, May 12, 2014 at 11:58 PM, A. Sundararajan
<sundararajan.athijegannathan at oracle.com> wrote:
> Hi,
> mozilla_compat.js provides only few things for transition -- not every Rhino
> shell extension is supported by that. Only a subset of "non-shell" rhino
> extensions are supported. JavaAdapter in mozilla_compat.js is a cover over
> nashorn's own Java.extend. Java.extend, Java.type - are stricter in that
> errors/exceptions are preferred compared to silently returning
> false/providing empty method etc.
> Thanks
> -Sundar
> On Monday 12 May 2014 09:57 PM, David P. Caldwell wrote:
>> I don't know how much compatibility is the goal, and I may be doing
>> something wrong, but it looks like (running JDK 1.8.0_05) there are
>> three incompatibilities between the Rhino shell and the
>> mozilla_compat.js implementation provided with Nashorn.
>> There may be reasons for these incompatibilities. But just in case
>> there are not,
>> 1. readFile appears to be absent,
>> 2. readUrl appears to be absent,
>> 3. The JavaAdapter implementation no longer appears to silently
>> provide delegate methods that return null; instead the default
>> implementation throws UnsupportedOperationException.
>> Obviously I know how to work around these differences, but they cause
>> some software to need modification to run under Nashorn even with the
>> compatibility layer.
>> Thoughts?
>> -- David P. Caldwell
>> http://www.davidpcaldwell.com/

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