hehe, I was writing something similar: "in production stage TagAttributeImpl is only created once and then facelets cache mechanism keep this instance alive as part of Facelet memory structure. Thus if user did request to all Facelet instances (all *xhtml) in JSF application, it creates forest of Facelet instances, Facelet instances are trees, those trees have nodes (Tag instances) with leafs = TagAttribute instances. It this is true and if I remember well graph theory long time ago at university, each TagAttribute instance is unique and there exists only on path to it -> why is ValueExpression evaluated new on every request?"
In short (I must go home now ...) : ValueExpression can differ in expected type and facelets context. But can those values be really diffirent for same TagAttribute instance? If they are always same can ve cache ValueExpression instance forever? Leonardo Uribe píše v St 20. 10. 2010 v 15:45 -0500: > Hi > > I have an idea: why don't evaluate that condition on construction > time? > > In that case, EL will be scanned only once (when the Facelet or > Abstract Syntax Tree (AST) is build) and > not when the view is build, like is happening now. > > I have created an issue > > https://issues.apache.org/jira/browse/MYFACES-2951 > > and committed the code in trunk. > > Suggestions are welcome. > > Leonardo Uribe > > 2010/10/20 Jakob Korherr <[email protected]> > Hi Kočičák, > > There might be some ways to improve this, but we have to be > very > careful in making changes to that area, because the whole > composite > components + EL domain is not that easy. > > Actually the CompositeComponentELUtils.isCompositeComponentXYZ > methods > were introduced by myself when fixing the #{cc} issues we > encountered > in some MyFaces 2 alpha versions. Unfortunately I currently > don't > really have time to think about improvements here, sorry. But > I really > think that there is some room for improvements! > > Also I really like your idea of > isProcessingCompositeComponent. This > might be a good way, because if this is false we can skip the > #{cc} > check, because such expressions will certainly not occur > outside of a > composite component. If you have some spare time, a patch > would be > really great :) :) - otherwise please just open a JIRA issue > for this > one so that we don't loose sight of it. Thanks! > > Regards, > Jakob > > 2010/10/20 Werner Punz <[email protected]>: > > > Just my 2c without looking into the code, but I assume speed > improvements > > already can be gained by replacing the pattern matches, if > possible with a > > direct ll comparison. > > Regexps often are heavier than simple parsing or string > operations. > > > > Another thing might be that we add some caching mechanism on > this level > > which caches per request if possible. But I have not looked > into the code, > > so I am making wild assumptions here. > > > > I assume also that some speed still can be gained in this > area by better > > utilization of the improved tree walking api jsf2 provides. > > > > > > Werner > > > > > > Am 20.10.10 15:54, schrieb Martin Koci: > >> > >> Hi, > >> > >> > >> a issue to consider in > >> org.apache.myfaces.view.facelets.tag.TagAttributeImpl: > >> > >> > >> Methods > >> TagAttributeImpl.getMethodExpression and > >> TagAttributeImpl.getValueExpression use > >> CompositeComponentELUtils.isCompositeComponentXYZ methods > to detect if > >> current #{} contains cc expression. But consider following: > if user > >> migrates from facelets 1.2 to 2.0, this new cc detection > slows down > >> build view process. In one my test case VDL.buildView calls > >> CompositeComponentELUtils.isCompositeComponentXYZ approx > 3000 times per > >> build view with no match. isCompositeComponentXYZ is not > cheap method > >> because it uses Pattern.matches(). > >> > >> Are there possibilities to avoid this? For example is > possible have some > >> kind of "isProcessingCompositeComponent" method and skip > >> Pattern.matches() if false? We are in VDL.buildView here > and no > >> components are available yet, no use of methods like > >> UIComponent.isCompositeComponent(UIComponent) is possible. > >> > >> Any ideas? > >> > >> Regards, > >> > >> Kočičák > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > > > > > > > > > > > -- > Jakob Korherr > > blog: http://www.jakobk.com > twitter: http://twitter.com/jakobkorherr > work: http://www.irian.at >
