Hi Richard,
I have a comment to one of your questions:
On 24.7.2013 21:06, Richard Bair wrote:
- Would we benefit from a "full lazy" model for properties where we
only instantiate them if somebody adds a listener
We've done that in javafx.scene.transform.Affine. This is a class
representing a general Affine transformation matrix, so it has twelve
double properties. I'm probably not able to find the actual numbers we
measured back then, but here is what I can remember. We used the 3D
music chart JavaOne demo which operated with the matrices incredibly
heavily. In this case the properties made a big difference in
performance; with all the properties instantiated, even
DoubleProperty.get() shone brightly in profiler results. So we
introduced the "full lazy" properties which helped. Then we looked into
it a bit more but were not able to create similar condition with any
other use-case; the property getter is just a null check and a couple of
calls in addition. It seemed that the transform matrices were a special
case where some 3D algorithms call the matrix element getters too much,
so we've left it at that.
Regarding memory requirements of the "full lazy" properties, let me
state the obvious:
- if the property is not used at all, we have a reference and a double
instead of just a reference (worse unless in bucket)
- if getters/setters are called, we still have a reference and a double
instead of full instantiated property (better)
- if a listener is added, we have instantiated property and a double
instead of just the property (slightly worse)
So it looks like it would make best sense to introduce this for
properties that are often get/set but usually don't have listeners on
them. I'm not sure if such set exists and can be identified.
It's still a good idea to investigate, I just thought this was worth
mentioning.
Cheers,
Pavel
