Hi,
Leonardo Uribe píše v Po 25. 04. 2011 v 12:45 +0200:
> Hi
>
> 2011/4/19 Martin Koci <martin.kocicak.k...@gmail.com>
> Hi,
>
> is it possible to introduce performance hints in myfaces-core?
> Hints
> similar to javax.faces.component.visit.VisitHint but related
> to
> performance improvements. Example:
>
> For dataTable like:
> <a:dataTable
> <a:column>
> #{aExpression}
>
> it's completely unnecessary to save per-row state. Currently
> there is no
> elegant way how to do read-only table (state per-row is always
> maintained). If user wants (fast) readOnly table, he/she must
> extend
> UIData and re-implemenent setRowIndex method. But hint say
> "org.apache.myfaces.core.UIData.saveRowState"=false can solve
> it
> elegantly - if present (in component.getAttributes()) UIData
> skips
> row-state-saving and restoring methods entirely.
>
>
> Unfortunately, we can't do anything like that on default UIData
> implementation
> (it could breaks backwards behavior). I think we could include a
> property
> on tomahawk t:dataTable called "readOnly", that just skip all that
> code
> related to save/restore for rows. That could be better, and it has
> sense to
> put in tomahawk, because after all that is the right location for
> extend
> default jsf components.
Yes, this is one point of view and I agree with that "custom behaviour
belongs into custom component". I did exactly the same for my component.
But there are other topics to consider:
0) simple presence of performance hints in core does not break the
compatibility : the *usage* of that hint can break the compatibility -
so as usual, user must know what that parameter means and what it can
cause.
1) I think JSF implementation can break the specified functionality:
myfaces did it already with elResolvers sorting for example. But the
default must be always false for 100% compatibility with JSF
specification.
2) The hint technique is very common : another example from Java EE is
world JPA Query.setHint
3) Hints are a simple way to realize something "this should be in core"
but because of slow specification release cycle, you must wait a year or
two to get it officially specified in public API.
4) Ease of usage: for example, if you have only one readonly table in
whole project, creation of custom component for that purpose is an
overkill: simple <f:attribute name="oam.readOnly" value="true" /> is
much easier.
5) Internet is full of "JSF is slow". Although I know that is completely
untrue, "hinting the core" for more performance is a easy way which
allows users to express all they need without additional dependencies.
So, do you think we really can't put this feature in core? I mean the
"hints feature" generally, not readonly UIData - that was only an
example.
Regards,
Kočičák
>
> Anyway, I think it is possible to do some work on UIData to make it
> perform
> faster and better.
>
> Lifespan of those hints can be request
> (faceContext.attributes) or view
> (component.attributes)
>
> I don't think in this case it applies, but any configuration param for
> a view
> should be on a tag like f:view or something similar.
>
> regards,
>
> Leonardo
>
>
>
> WDYT?
>
> Regards,
>
> Kočičák
>
>
> See https://issues.apache.org/jira/browse/MYFACES-3111 too.
>
>
