How to properly implement JSObject to provide conversion of Gson JsonElement objects?

[Daniel Einspanjer]

Yes, that is the bug.

My work around isn't great, I just had to avoid using any form of custom
JSObject. Instead, I do an eval('new Object()') to get a holder and put my
object and functions inside it via put().

-Daniel

On Thu, Jun 1, 2017, 6:30 PM Jesse Schulman <jesse at dreamtsoft.com> wrote:

> Ironically, I'm hitting a similar issue with a library doing an
> Object.keys() call against a custom JSObject, can you share the solution
> you've taken?
>
> Also, I'm guessing this is the RFE you created:
> https://bugs.openjdk.java.net/browse/JDK-8181203?jql=text%20~%20%22Object.keys%20nashorn%22
>
> Thanks!
> Jesse
>
> On Tue, May 30, 2017 at 9:34 AM Daniel Einspanjer <deinspanjer at gmail.com>
> wrote:
>
>> Thank you, yes that is very similar to the approach I went down.
>> Ultimately I hit another roadblock that forced me to approach the entire
>> issue differently.  The JS library I am interacting with uses Object.keys()
>> and currently, Nashorn doesn't support Object.keys() calls with custom
>> JSObjects.  I filed an RFE for that, but due to the issue, I'm having to
>> avoid using JSObject entirely.
>>
>> Thanks again for your reply.
>>
>> -Daniel
>>
>> On Tue, May 30, 2017 at 12:29 PM Jesse Schulman <jesse at dreamtsoft.com>
>> wrote:
>>
>>> If you haven't got this working yet, one possible solution is to return
>>> anonymous inner AbstractJSObject that returns true for isFunction calls:
>>>
>>>    public Object getMember(String name) {
>>>       if ("map".equals(name)) {
>>>          return new AbstractJSObject() {
>>>             @Override
>>>             public Object call(Object thiz, Object... args) {
>>>                // delegate to your JsonArray.map method from this
>>> annonymous inner class
>>>                // in your example nashorn should pass you a single
>>> instance of ScriptObjectMirror for args that returns true for isFunction()
>>> call
>>>             }
>>>
>>>             @Override
>>>             public boolean isFunction() {
>>>                   return true;
>>>             }
>>>          };
>>>       }
>>>
>>>       return null;
>>>    }
>>>
>>>
>>> Hope that helps!
>>> Jesse
>>>
>>> On Thu, May 25, 2017 at 1:11 PM Daniel Einspanjer <deinspanjer at gmail.com>
>>> wrote:
>>>
>>>> I have a project that makes extensive use of the Google Gson library.
>>>>
>>>> In this particular case, I have a JsonArray object (which implements
>>>> iterable) containing a collection of objects.  In pure JSON it would
>>>> look
>>>> like this:
>>>>
>>>> [ 1, true, {"a": "b"}, [1,2] ]
>>>>
>>>> In Gson JsonElements, it looks like this:
>>>>
>>>> arr = new JsonArray();
>>>> arr.add(1);
>>>> arr.add(true);
>>>>
>>>> obj = new JsonObject();
>>>> obj.addProperty("a", "b");
>>>>
>>>> arr.add(obj);
>>>>
>>>> innerArr = new JsonArray();
>>>> innerArr.add(1);
>>>> innerArr.add(2);
>>>>
>>>> arr.add(innerArr);
>>>>
>>>> I am calling a Javascript function in Nashorn that is trying to do a map
>>>> over this array:
>>>>
>>>> nash.eval("function doIt(arr) { print(arr.map(function(item) { return
>>>> (typeof item); })); }");
>>>>
>>>> So, in order for this to work with my own arbitrary object (JsonArray),
>>>> I
>>>> believe I need to implement JSObject.
>>>>
>>>> I created the wrapper class that implements it, using the underlying
>>>> JsonArray object as a delegate.  things like isArray() and such are
>>>> trivial, but I'm having trouble with the map.
>>>> I have a map method that takes a functional interface which is available
>>>> for the JsonArray object.
>>>>
>>>> Nashorn calls getMember("map") when the doIt function is executed.  I
>>>> cannot figure out how to give it an appropriate function reference to my
>>>> JsonArray.map method.
>>>> I was able to handle getMember("toString") easily enough, but the
>>>> problem
>>>> is that method doesn't take any arguments, so returning a simple
>>>> Callable<Object> is fine for it, but map is going to take arguments
>>>> that I
>>>> don't know about ahead of time.
>>>>
>>>> I would really appreciate some assistance here.  Thanks.
>>>>
>>>> -Daniel
>>>>
>>>