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https://issues.apache.org/jira/browse/MYFACES-2873?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Leonardo Uribe resolved MYFACES-2873.
-------------------------------------
Resolution: Fixed
Fix Version/s: (was: 2.0.2)
2.1.2
2.0.8
1.2.11
I reviewed the stack trace and the problem is an EL expressions is created from
a location where no ExternalContext is setup (TrinidadFilter).
The comparator or predicate used to sort/filter EL resolvers should be created
by FacesConfigurator and attached to RuntimeConfig object, so it just can be
used from Application implementation instance later without retrieve
ExternalContext instance. I thought it was something related to the algorithm
but at the end it was a side effect. Thanks for the report.
> Provide a way to change the order of ELResolvers
> ------------------------------------------------
>
> Key: MYFACES-2873
> URL: https://issues.apache.org/jira/browse/MYFACES-2873
> Project: MyFaces Core
> Issue Type: Improvement
> Affects Versions: 1.2.9, 2.0.1
> Reporter: Jakob Korherr
> Assignee: Leonardo Uribe
> Fix For: 1.2.11, 2.0.8, 2.1.2
>
> Attachments: MYFACES-2873.patch
>
>
> When using CDI or Spring or any other framework/lib that provides a custom
> ELResolver there can be performance problems, because the custom ELResolvers
> from the faces-config are plugged in pretty early in the resolver chain.
> For CDI this means that for lots of trivial ELExpressions (like Array or Map
> value lookups) the CDI-ELResolver gets called and this resolver is not very
> performant, because it has to go through all Objects which are handled by CDI
> to find the fitting one. And in the most cases it won't find a fitting
> object, because the requested value is not handled by CDI.
> JSF currently only allows to sort the ELResolvers from different faces-config
> files, but not to change the order of predefined ELResolvers (like e.g.
> MapELResolver). Thus talking with Mark Struberg and Gerhard Petracek we came
> up with a Comparator<ELResolver> solution for this problem.
> The user can define a Comparator<ELResolver> via a web.xml config param and
> this comparator will be used to sort the ELResolvers before they are applied
> (but of course, only once). In addition we provide 3 default implementations:
> one to put every ELResolver from the faces-config to the front, one to put
> them to the back and one optimized for OpenWebBeans.
> This solution gives you many improvements:
> - you can tune your application by a customized order of ELResolvers
> - you don't need MyFaces implementation classes, but only a simple Comparator
> - if you switch to Mojarra or a earlier version of MyFaces, the ordering
> just won't work, but the behavior of the ELResolvers is the same
> The context-parameter will look like this (for the OWB-optimized resolver):
> <context-param>
> <param-name>org.apache.myfaces.EL_RESOLVER_COMPARATOR</param-name>
>
> <param-value>org.apache.myfaces.el.unified.OpenWebBeansELResolverComparator</param-value>
> </context-param>
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