I don't see us adding 100s of OS-specific API calls, but even if we did,
going down the path of exposing them as Mac APIs or Windows APIs,
doesn't really seem like the direction we want to go. Whatever we do
needs to balance the desire to integrate with, e.g., the macOS or
Windows platform with a desire to leave the door open for it to later be
implemented on the other platform(s). And the most cross-platform way to
do that from an API point of view is by defining API that delivers the
desired functionality in as platform-neutral a way as possible. It also
needs to fit cleanly into the existing API.
So in the specific case of a quit handler, we could define a platform
API that an app could call to register a handler that gets called if the
platform quit menu is selected and is able to cancel the Quit
action(basically, that's what is being proposed). We could decide to
provide some way for an app to query whether it is supported, but maybe
we just don't need to worry about it in this specific case. We could
just document that it will get called when the platform quit action is
called, if there is such an action on that platform. Other than maybe
mentioning in the docs that the macOS system menu "quit" action is an
example of an action that would invoke this, it doesn't need to be
platform-specific. One question to answer is whether we should just put
this in the Platform class (where we have other similar "global"
application state), the Application class (which has the life-cycle
APIs), or somewhere else (which might make sense if we wanted to define
an analog to the AWT Desktop class, although the existing Platform class
already has some APIs like this).
-- Kevin
On 9/19/2022 1:46 PM, Andy Goryachev wrote:
Thank you, Kevin. Your insightful feedback always pulls the
discussion in the right direction.
The initial problem we are facing is access to Mac menu in general and
additional API specifically. I can see a possibility of extending the
list of APIs that app devs would want on Mac growing, so there should
be a better way to add them. Using hacks like com.apple.eawt, or
system properties is probably not the best solution. Ideally, there
should be away that does not require creative linking of stub classes
on non-Mac platforms, i.e. we should be able to use a single code base
for all the platforms.
ConditionalFeature might work well internally for openjfx, but I don't
think it is a good solution for actually exposing the platform APIs to
the user.
So, in order to provide platform-specific API in such a way that still
allows for a single code base for multiple platform, and one that
potentially scales to tens or hundreds of API calls, I see two solutions:
1. one start starts with a single entry point, like PlatformAPI,
described earlier.
2. a lookup-based approach, where the client code requests a (possibly
fine-grained and narrowly defined) implementation from the system.
For example:
IMacMenu impl = PlatformAPI.lookup(IMacMenu.class);
(where IMacMenu is an interface that, in this example, provides access
to Mac menu, adding shutdown listeners, and so forth).
if we are on windows, this method either returns null or throws an
exception, if we are on Mac, we get a working instance (a singleton or
a new instance each time, depending on the circumstances).
This way we are free to extend or version the APIs without modifying
the core classes.
PlatformAPI.isSupported(IMacMenu.class) might provide a way to see
whether the capability is present.
The platform-specific interfaces like IMacMenu might in turn extend
some base interface that provides introspection into common
properties, such as version, description, possibly a list of other
similar capabilities that the platform supports (may be a number of
earlier versions?) and so forth.
What do you think?
-andy
*From: *openjfx-dev <openjfx-dev-r...@openjdk.org> on behalf of Kevin
Rushforth <kevin.rushfo...@oracle.com>
*Date: *Monday, 2022/09/19 at 09:33
*To: *openjfx-dev@openjdk.org <openjfx-dev@openjdk.org>
*Subject: *Re: Provide Quit handler for system menu bar
I like the idea of looking at this holistically, even if we do end up
adding such features one at a time.
As for how to expose such an API, I don't much like the idea of
exposing the underlying platform explicitly unless there is no viable
alternative. A better approach is one where a feature is optional
based on whether the platform you are running on supports that
feature. Especially given, as you pointed out, that features that are
only available in one platform today might make their way into other
platforms tomorrow. As for how to let an application know whether they
can use a particular API, we already have ConditionalFeature, so
adding to that would be a reasonable thing to consider.
-- Kevin
On 9/19/2022 9:06 AM, Andy Goryachev wrote:
Greetings!
Thank you for proposing a solution, Florian. I wonder if we
should extrapolate the problem further. Given the fact that app
developers always need access to platform specific APIs, be it
integration with Mac menu, perhaps we should consider a way to do
so in such a way that does not require various tricks.
For example, we might invent a way to query whether we are running
on a certain platform and get the corresponding APIs. Let's say
the class is PlatformAPI:
These methods allow for querying whether the specific platform
APIs are available
PlatformAPI.isWindows();
PlatformAPI.isMacOS();
PlatformAPI.isLinux(); // isUnix()? isPosix() ?
and these will actually return a service object that provides
access to the APIs, or throws some kind of exception:
IWindowsAPI PlatformAPI.getWindowsAPI();
IMacOSAPI PlatformAPI.getMacOSAPI();
the service object returned by one of these methods might provide
further information about the platform version, as well as access
to platform-specific APIs.
Another thought is perhaps we ought to think about expanding
functionality that became available on every platform in the XXI
century (example: going to sleep/hibernate). Possibly external
shutdown via Mac menu or a signal discussed by the OP would be
considered as platform-independent.
What do you think?
-andy
*From: *openjfx-dev <openjfx-dev-r...@openjdk.org>
<mailto:openjfx-dev-r...@openjdk.org> on behalf of Florian
Kirmaier <florian.kirma...@gmail.com>
<mailto:florian.kirma...@gmail.com>
*Date: *Tuesday, 2022/09/13 at 08:11
*To: *openjfx-...@openjdk.java.net <openjfx-...@openjdk.java.net>
<mailto:openjfx-...@openjdk.java.net>
*Subject: *Provide Quit handler for system menu bar
Hi Everyone,
In one project, we have to handle the quit-logic for MacOS ourselves,
when the <quit app> menu entry is used.
As background information - this menu entry is set in the
class com.sun.glass.ui.mac.MacApplication.
It's basically hard coded. Currently, in this project, the menu
entry doesn't work in some cases.
My Solution would be:
Provide a method "Platform.setQuiteHandler(Supplier<Boolean>)"
This handler is called when quit <appname> from the menu is called.
If the handler returns true, all windows are closed. Otherwise,
nothing happens.
It would look like the following:
```
/**
* Sets the handler to be called when the application is about to
quit.
* Currently, this can only happen on MacOS.
*
* This handler is called, when the user selects
* the "Quit <appname>" from the application menu.
* When the provided handler returns true,
* the application will close all windows.
* If the handler returns false, the application will not quit.
*
* @param The new quit handler.
*/
public static void setQuitHandler(Supplier x) {
...
}
```
I've created a ticket for this topic.
https://bugs.openjdk.org/browse/JDK-8293700
I've got a working version for this change.
According to Kevin Rushforth this need a prior dicussion on the
mailing list.
Any opinion regarding this?
I could provide a pullrequest, if someone is interested.
Florian Kirmaier
