setNashornGlobal usage

[Tobias Schlottke]

Hi Jim,

this example shows it pretty well:

https://gist.github.com/tobsch/6026942

as the script itself is very simple and does nothing special. It's only its invocation or doPrivileged to be precise.

This is the profiler output:


Any ideas?

Best,

Tobias


Am 17.07.2013 um 18:23 schrieb Jim Laskey (Oracle) <james.laskey at oracle.com>:

> Tobias,
> 
> We'll look into removing the doPrivileged on first entry (security is checked elsewhere), but we need to do a security assessment before proceeding.
> 
> That said, I would recommend as a best practice to use a per-thread JavaScript loop instead, to avoid such issues.  I generally use a java.util.concurrent.LinkedBlockingQueue to "feed" the loop from other threads.
> 
> Cheers,
> 
> -- Jim
> 
> 
> 
> 
> On 2013-07-17, at 12:37 PM, Tobias Schlottke <tobias.schlottke at gmail.com> wrote:
> 
>> Hi there,
>> 
>> I've built a small case where I evaluate a compiled script equipped with a custom bindings.
>> The script is equipped with some variables and and compiled like this:
>> 
>>     engine.put("shopId", "test");
>>     runner = (Bindings) engine.compile(ad.getCondition_script().getCode()).eval();
>> 
>> afterwards, I execute the "run" method on the object returned by eval() like this:
>> 
>>   return (MyCustomObject) engine.invokeMethod(runner, "run", attr);
>> 
>> the run method does local compilations but does not change anything so basically the runner is immutable.
>> I access it from various threads.
>> 
>> When profiling the code I see a lot of time spent in java.security.AccessController.doPrivileged() which is invoked in setNashornGlobal() if the globals changed.
>> I'm a bit unsure what changed globals really mean because in my case nothing (either context nor bindings) changed and I wonder if it is necessary.
>> 
>> Best,
>> 
>> Tobias
>