A WIP for JDK-8238080 for review/discussion (Re: "Internal review ID 9063426: "FXMLLoader: if script engines implement javax.script.Compilabel compile scripts"

Kevin Rushforth kevin.rushforth at oracle.com
Thu Apr 2 23:21:49 UTC 2020

Hi Rony,

I see that you updated the PR and sent it for review.

Before we formally review it in the PR, let's finish the discussion as 
to whether this is a useful feature, and if so, what form this feature 
should take.

 From my point of view, this does seem like a useful feature. Would 
other users of FXML benefit from it?

I'm not certain whether we want it to be implicit, compiling the script 
if the script engine in question implements Compilable, or via a new 
keyword or tag. What are the pros / cons?

What do others think?

In either case, we would need to make sure that this doesn't present any 
security concerns in the presence of a security manager. As long as a 
user-provided class is on the stack, it will be fine, but we would need 
to ensure that.

-- Kevin

On 4/2/2020 10:41 AM, Rony G. Flatscher wrote:
> After merging master, applying some fixes and changing the title to reflect the change from WIP to a
> pull request I would kindly request a review of this pull request!
> Here the URL: <https://github.com/openjdk/jfx/pull/129>, title changed to: "8238080: FXMLLoader: if
> script engines implement javax.script.Compilable compile scripts".
> ---rony
> On 28.02.2020 19:22, Rony G. Flatscher wrote:
>> Here is a WIP [1] implementation of [2]. The WIP is based on [3], which is currently in review, and
>> has an appropriate test unit going with it as well, please review.
>> There should be no compatibility issue with this implementation.
>> Discussion: another solution could be to not compile by default. Rather compile, if some new
>> information is present with the FXML file which cannot possibly be present in existing FXML files.
>> In this scenario one possible and probably simple solution would be to only compile scripts if the
>> language process instruction (e.g. <?language rexx?>) contains an appropriate attribute with a value
>> indicating that compilation should be carried out (e.g.: compile="true"). This way only FXML with
>> PIs having this attribute set to true would be affected. If desired I could try to come up with a
>> respective solution as well.
>> ---rony
>> [1] "Implementation and test unit": <https://github.com/openjdk/jfx/pull/129>
>> [2] "JDK-8238080 : FXMLLoader: if script engines implement javax.script.Compilable compile scripts":
>> <https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8238080>
>> [3] "8234959: FXMLLoader does not populate ENGINE_SCOPE Bindings with FILENAME and ARGV":
>> <https://github.com/openjdk/jfx/pull/122/commits>
>> On 24.01.2020 16:26, Kevin Rushforth wrote:
>>> Thank you for filing this enhancement request. As an enhancement it should be discussed on this
>>> list before proceeding with a pull request (although a "WIP" or Draft PR can be used to illustrate
>>> the concept).
>>> For my part, this seems like a reasonable enhancement, as long as there are no compatibility
>>> issues, but it would be good to hear from application developers who heavily use FXML.
>>> -- Kevin
>>> On 1/24/2020 7:21 AM, Rony G. Flatscher wrote:
>>>> Just filed a RFE with the following information:
>>>>     * Component:
>>>>         o JavaFX
>>>>     * Subcomponent:
>>>>         o fxml: JavaFX FXML
>>>>     * Synopsis:
>>>>         o "FXMLLoader: if script engines implement javax.script.Compilabel compile scripts"
>>>>     * Descriptions:
>>>>         o "FXMLLoader is able to execute scripts in Java script languages (javax.script.ScriptEngine
>>>>           implementations) if such a Java script language gets defined as the controller language in
>>>>           the FXML file.
>>>>           If a script engine implements the javax.script.Compilable interface, then such scripts
>>>> could
>>>>           be compiled and the resulting javax.script.CompiledScript could be executed instead using
>>>>           its eval() methods.
>>>>           Evaluating the CompiledScript objects may help speed up the execution of script
>>>> invocations,
>>>>           especially for scripts defined for event attributes in FXML elements (e.g. like
>>>> onMouseMove)
>>>>           which may be repetitevly invoked and evaluated."
>>>>     * System /OS/Java Runtime Information:
>>>>         o "All systems."
>>>> Received the internal review ID: "9063426"
>>>> ---rony

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