Is there a way to reference the engine from a linker?

Discussion:

Paulo Lopes

2018-03-15 19:02:40 UTC

Hi,

I'm writing a guarded linker to allow custom casting from JSObject to Vertx
custom types. So far so good, the basic tests seem to work but I think I'm
writing too much boiler plate code as I need in many times to have an
intermediate conversion from JSObject to Map or List.

So I know that in the engine I could call Java.asJSONCompatible() but I
don't see how I could get a reference to the engine in the linker.

Could anyone see a way or let me know if there is a open API to do this?

Thanks!
Paulo

Sundararajan Athijegannathan

2018-03-16 01:28:15 UTC

Permalink

Hi,

Dynalink and its pluggable linkers are independent of Nashorn. If you
want to access the current engine, you've to arrange to pass it.

Thanks,
-Sundar

Post by Paulo Lopes
Hi,
I'm writing a guarded linker to allow custom casting from JSObject to Vertx
custom types. So far so good, the basic tests seem to work but I think I'm
writing too much boiler plate code as I need in many times to have an
intermediate conversion from JSObject to Map or List.
So I know that in the engine I could call Java.asJSONCompatible() but I
don't see how I could get a reference to the engine in the linker.
Could anyone see a way or let me know if there is a open API to do this?
Thanks!
Paulo

Attila Szegedi

2018-04-04 17:20:50 UTC

Permalink

Sorry for an awfully late response, but hope it might still help: Java.asJSONCompatible delegates on the Java side to jdk.nashorn.api.scripting.wrapAsJSONCompatible. It’s part of Nashorn’s supported public API, so it should be fine for you to call it.

I’m actually wondering how useful is that API method - you need to pass a “homeGlobal” parameter, and honestly I’m not really sure how you’d obtain that. Maybe Sundar has an idea.

Attila.

Paulo Lopes

2018-04-04 17:28:35 UTC

Permalink

Hi,

I've worked around it by using:

ScriptUtils.convert(obj, Map.class)

When ever I needed to get a script object as a map or replacing the class with List.class when I need a list...

Is that a safe way to do it?

Original Message
From: ***@gmail.com
Sent: April 4, 2018 7:21 PM
To: ***@redhat.com
Cc: nashorn-***@openjdk.java.net
Subject: Re: Is there a way to reference the engine from a linker?

Sorry for an awfully late response, but hope it might still help: Java.asJSONCompatible delegates on the Java side to jdk.nashorn.api.scripting.wrapAsJSONCompatible. It’s part of Nashorn’s supported public API, so it should be fine for you to call it.

I’m actually wondering how useful is that API method - you need to pass a “homeGlobal” parameter, and honestly I’m not really sure how you’d obtain that. Maybe Sundar has an idea.

Attila.

Attila Szegedi

2018-04-04 17:50:21 UTC

Permalink

Oh, good one. Yes, I think that’ll do. It engages Nashorn’s built-in linker chain to find an appropriate conversion.

Attila.

Post by Paulo Lopes
Hi,
ScriptUtils.convert(obj, Map.class)
When ever I needed to get a script object as a map or replacing the class with List.class when I need a list...
Is that a safe way to do it?
Original Message
Sent: April 4, 2018 7:21 PM
Subject: Re: Is there a way to reference the engine from a linker?
Sorry for an awfully late response, but hope it might still help: Java.asJSONCompatible delegates on the Java side to jdk.nashorn.api.scripting.wrapAsJSONCompatible. It’s part of Nashorn’s supported public API, so it should be fine for you to call it.
I’m actually wondering how useful is that API method - you need to pass a “homeGlobal” parameter, and honestly I’m not really sure how you’d obtain that. Maybe Sundar has an idea.
Attila.