Re: Lambdafication (was Re: Default methods in JFX-8)

Kevin Rushforth Mon, 07 Oct 2013 04:29:14 -0700


5. Should we enable more -Xlint warnings in OpenJFX build?


6. Any chances anything of this can still go in 8 (e.g. get rid of warnings

We have 2 weeks where we can still accept P4-P5 bugs into FX 8, andgetting rid of warnings would be a P4 bug. I guess it depends on howintrusive the changes are and whether someone has time to review it inthe next two weeks.


-- Kevin



Sven Reimers wrote:

Ok. So here are the results of trying to add lambda and diamond to the
controls module:

1. A lot of generics and typing to be fixed (esp. in tests). Seems you can
get  some anonymous inner classes type checked by the compiler, but not the
lambda equivalent.. very interesting.

2.  279 Files modified (including tests)

3. A lot of the automatic replacements could probably be nicer e.g.

ft.setOnFinished(new EventHandler<ActionEvent>() {
                        @Override public void handle(ActionEvent
actionEvent) {
                          getChildren().remove(tm.textNode);
                        }
                    });

was replaced to:

ft.setOnFinished((ActionEvent actionEvent) -> {
    getChildren().remove(tm.textNode);
});

most unobtrusive code probably:

ft.setOnFinished((actionEvent) -> getChildren().remove(tm.textNode));

4. A lot of illegal forward reference errors - these were result of missing
this in the automatic transformation from anonymous inner to lambdas (seems
the rules are not identical - you have to add "this." as prefix if using
lambdas - not sure this is the expected way it should work)

5. Should we enable more -Xlint warnings in OpenJFX build?

6. Any chances anything of this can still go in 8 (e.g. get rid of warnings

7. Probably more things I just can't think of at the moment...

How to take this forward? If there is interest in the change I could make
available...

Comments? Ideas?

-Sven



On Fri, Oct 4, 2013 at 2:19 PM, Sven Reimers <sven.reim...@gmail.com> wrote:

Oh and btw - would you go for lambda with or without additional type info
 before parameter name?

-Sven


On Fri, Oct 4, 2013 at 2:05 PM, Sven Reimers <sven.reim...@gmail.com>wrote:

Ok. Here you go...

I just did an inspection run for the controls module and my IDE came up
with  (drum roll) 888 possible lambda conversions..

Looking through them I discovered that usage of <> (aka diamond syntax)
is   not used (or at least not used a lot) in at least the controls
modules. My IDE showed me 1171 occurrences.

Is there a good reason not to use diamonds?

Will now try to apply all those changes and figure out if this still
builds... up next: go through the other modules...

-Sven


On Fri, Oct 4, 2013 at 1:35 AM, Richard Bair <richard.b...@oracle.com>wrote:

Brian was telling me at J1 that whether parallel gets you performance or
not depends on the size of the collection and the complexity of the work to
perform. There is definitely a point at which parallel helps -- and a point
at which it hurts.

Richard

On Oct 3, 2013, at 3:33 PM, Hervé Girod <herve.gi...@gmail.com> wrote:

Here is a nice example, taking advantage of the ease of going

parallel. Apparently the performance without parallel will also further
improve.
http://blog.hersen.name/blog/2013/10/01/project-lambda-it-was-worth-the-wait/

Hervé

Sent from my iPad

On 4 oct. 2013, at 00:20, David Grieve <david.gri...@oracle.com>

wrote:

And what about Stream? I like the declarative code that comes from

using Stream and I can see places in the code where Stream could be used,
but I wonder about its performance relative to iterators and/or enhanced
for loops.

On Oct 3, 2013, at 4:45 PM, Richard Bair <richard.b...@oracle.com>

wrote:

Hello, OpenJFX Community.

There's a question about using Java 8 features in FX.

I've been working on the support for InputMethods in JFXPanel which

is an important feature for many users who speak hieroglyphic languages.

The issue is tracked under:

https://javafx-jira.kenai.com/browse/RT-13248

In order to have a high-quality support we need to change

javafx.scene.input.InputMethodRequests interface and introduce 3 new
methods. This is not needed for pure FX applications right now, but
absolutely required for InputMethods in the JFXPanel. However, the
interface is public and it was present since FX2.0, so changing it would
become a breaking change. So the only way to avoid the problem is using the
default methods. Those would return some stub values, the JDK is OK with
that, as it would not crash or throw exceptions, but text composition would
not work correctly.

I know that we want to avoid using the Java 8 features in the

JFX-8, so I wanted to ask - is it OK to use the default methods here?

If you are staying away from JDK8 features for the JFX78 backport,

don't worry.  There are more issues with new JDK8 APIs than with the new
language features.

For example there were default methods put into some collections

classes that we solved by pushing them down to the first implements.  But
the Date and Time picker depends on the new time package.  The threeten
backport won't be updated until after 8 ships, so that has been removed so
far.

I'de be interested to know what a wholesale lamdaization would

result in speed wise and code size wise (both source and compiled).  From
what I can tell the IDEs can lambda and de-lambda fairly easily, so it jsut
makes the backport more of a busy work proposition.  If there were
performance gains it would also make a great front page story in the next
java magazine or a case study..

After having used Lambda's for JavaOne, I'd love to make the

conversion, even if in the end the performance was the same, because the
savings in noise in the Java files is so big. At one time I just took the
concurrent classes and lambda-ized them to measure the impact on those
classes. You could maybe pick a package and just lambda-ize that one
package and see what happens in terms of size reduction. We might see:

 + A reduction in the overall class size (not pack-200'd)
 - An increase in startup time (have to spin up synthetic classes

created at usage time)

 +/- And increase or decrease in performance
 + A decrease in source code

It would be interesting to get some data for these points and see

what effect lambda's have. Especially if an IDE can just do it in bulk…

Richard

--
Sven Reimers

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--
Sven Reimers

* Senior Expert Software Architect
* NetBeans Dream Team Member: http://dreamteam.netbeans.org
* Community Leader  NetBeans: http://community.java.net/netbeans
                              Desktop Java:
http://community.java.net/javadesktop
* Duke's Choice Award Winner 2009
* Blog: http://nbguru.blogspot.com

* XING: https://www.xing.com/profile/Sven_Reimers8
* LinkedIn: http://www.linkedin.com/in/svenreimers

Join the NetBeans Groups:
* XING: http://www.xing.com/group-20148.82db20
* NUGM: http://haug-server.dyndns.org/display/NUGM/Home
* LinkedIn: http://www.linkedin.com/groups?gid=1860468
                   http://www.linkedin.com/groups?gid=107402
                   http://www.linkedin.com/groups?gid=1684717
* Oracle: https://mix.oracle.com/groups/18497

Re: Lambdafication (was Re: Default methods in JFX-8)

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