[jsr-314-open] [NEW - MR] Add ExpressionFactory to "11.4.6 Delegating Implementation Support"

[Ed Burns]

>>>>> On Tue, 18 Aug 2009 13:16:06 +0100, Pete Muir <pmuir at redhat.com> said:


PM> I'm not sure why this requires any changes to Unified EL, the change  
PM> is needed in JSF (see changes I suggested).

Perhaps I misunderstood your feature request, then.  Let me restate it
in my own words and you can tell me if I understand you.

You want to make it so the ExpressionFactory instance returned from
Application.getExpressionFactory() is subject to the decoration
construction pattern that we use for all the rest of our decoratable
artifacts.  Is that correct?

The problem is that the JSF spec says the application must simply call

JspFactory.getDefaultFactory().getJspApplicationContext(servletContext).getExpressionFactory();

We don't maintain a reference to the instance that is returned.  Even if
we started doing so, and performed the wrapping as an spec requirement
of the javax.faces.application.Application implementation, you'd miss
out on anyone who is creating expressions with the ExpressionFactory
that you get from any other way than the Application instance.  

In other words, I assert that to satisfy your request, we have change
the contract of how the canonical ExpressionFactory instance is created,
which is currently the responsibility of the EL implementation.

Ed


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