Accessibility provider classpath

[Vladimir Petko]

Hi,

Samuel, please correct me if I'm wrong. The requirement is for the
per-user (or system-wide) enablement of accessibility. The
per-application setup is a bad user experience, and it would be nice
to have a single point - properties file - that enables it.

Java 8 achieves this by putting the accessibility provider jar in the
'ext' directory. Java 11 and up requires including an accessibility
provider in the modules files.

Any updates and fixes to the accessibility provider will require new
releases of the openjdk package in Debian and Ubuntu. Adding
accessibility providers to the build dependencies of the openjdk
package also creates a circular build dependency that might introduce
issues requiring careful synchronization between releases.

I propose to add a new property 'java.accessibility.module_path'. The
property will contain the list of locations of accessibility modules.
Toolkit will construct the classloader using this path and the system
class loader as a parent. Older releases will ignore this property.

This feature will allow installation of the accessibility provider
separate from the openjdk package and will satisfy the requirement of
per-user and system-wide enablement of the accessibility provider.

Best Regards,
 Vladimir.

On Thu, Sep 21, 2023 at 9:48 AM Philip Race <philip.race at oracle.com> wrote:
>
> Can you explain your need for this (a lot) better ?
>
> The location and loading is specified to be done by
> java.util.ServiceLoader.
> Whilst this might be possible by some enhanced syntax, which if present
> invokes ServiceLoader specifying a ClassLoader for this jar file, it
> would clearly be new API and only for future releases.
> NB it would also be fiddly to implement as the value of the property is
> a list of class names and
> you can't add jar names to that without breaking older JDKs and
> so you'd need some way to match new lines referencing the JAR file for
> each class ..
>
> And likely we'd want to have new APIs like this - if they make sense - to
> be focused on a module, not a jar, but building a runtime image from
> modules using jlink is a normal thing to do, so I'm not sure what such
> an API would look like and seems to be not what you want.
>
> I also don't understand  the use case / problem.
> Whatever launches your application can set
> -Djavax.accessibility.assistive_technologies=<..>
> and  set the -cp to include your jar and you don't need to do anything
> to the runtime image.
>
> -phil
>
> On 9/20/23 1:33 PM, Vladimir Petko wrote:
> > Hi,
> >
> > Java accessibility.properties (.accessibility.properties) allows
> > setting the class name of the accessibility provider but not the jar
> > file containing it.
> >
> > Was there any consideration that prevents this feature from being
> > implemented, such as security?
> >
> > It would be nice to have it implemented to allow system-wide/per-user
> > configuration of the accessibility provider without rebuilding the
> > runtime image.
> >
> > If this is something acceptable, I am happy to create an enhancement
> > issue and work on it.
> >
> > Best Regards,
> >   Vladimir.
>