[jbossseam-issues] [JBoss JIRA] Created: (JBSEAM-3660) Add option to move Seam imported namespaces into a CompositeNamespace

[Michael Youngstrom (JIRA)]

Add option to move Seam imported namespaces into a CompositeNamespace
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                 Key: JBSEAM-3660
                 URL: https://jira.jboss.org/jira/browse/JBSEAM-3660
             Project: Seam
          Issue Type: Feature Request
          Components: EL
    Affects Versions: 2.0.3.CR1
            Reporter: Michael Youngstrom
            Assignee: Michael Youngstrom
             Fix For: 2.1.1.CR1


In some profiling I've done recently SeamELResolver is a major hot spot.  In the current SeamELResolver code the resolver currently checks the root namespace to resolve the property.  If it is not found there then the SeamELResolver will check all of the imported namespaces to see if the value can be resolved by prepending the namespace.  In Seam 2.0.3 this results in 14 calls to Contexts.lookupInStatefulContexts() which is a rather expensive operation since it asks each one of the 8 scopes for the value.  Often times each check involves several string appends and several hashmap lookups.

If most of the el requests are user defined seam components this is not much of a problem.  However, frequently this is not the case.  For example, In an h:dataTable every time the "var" value is requested in an expresion it will have to go through all 14 Contexts.lookupInStatefulContexts() every time since it will not find the dataTable var in any of the seam scopes.

Same thing for the s:selectItems component.  A great component but it makes 5 or so EL requests for each option in the list which can begin to add up quickly.  Another case is people who are using Spring (my problem) :).

I think it would be a good idea to add an option to make SeamELResolver a better citizen in the ELResolver chain.  One way to do this is to add an option to core:init that would move all Seam imported namespaces into a single child namespace.  the option could look like this:

<init:core core-imported-prefix="seam"/>

This would be completely optional.  It would move all namespaces that begin with "org.jboss.seam" into a seam composite namespace.  The only impact it would have is that the developer would need to prefix the standard component with "seam." like #{seam.locale}.  There are not a lot of standard seam components that are frequently accessed through EL. #{seam.messages} comes to mind.  But for projects that need it this would make SeamELResolver resolution 93% faster.  This wouldn't create any backwards compatibility problems because it would be completely optional.  But at the same time projects that need to take advantage of it can.

I can prepare a patch for this if the idea is approved.

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