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From Craig Longman <cra...@begeek.com>
Subject Re: incorporating EL support
Date Thu, 12 Sep 2002 16:45:38 GMT
On Thu, 2002-09-12 at 12:14, peter lin wrote:
> 
> 
> You should know that JSP2.0 includes EL built in.  the early access
> implementation of JSP2.0 uses JSTL's el.

oh, ok.  well, that's good news.  i guess that splits my question into a
couple pieces:

1) jsp2.0 including EL, does that mean that the way one evaluates an EL
parameter will change, or that explicit evaluation will no longer be
necessary
2) is there a way of determining ( in a tag ) to determine what the JSP
level container we're executing in.  then the tag (during a phase-in
period at least) could determine whether to explicitly evaluate it or
not.

and a third question i suppose:
3) is explicitly evaluating EL really as simple as calling
ExpressionEvaluatorManager.evaluate() (as below), or is there some other
prep/setup work i haven't noticed yet in the bowels of the current jstl
package?

> You may want to look at the draft spec to familiarize yourself with the
> changes that will occur when JSP2.0 is released. 

i'll try and track it down, thanks.

> peter lin
> 
> Craig Longman wrote:
> > 
> > hi there,
> > 
> > i'm just starting out with jsp/taglibs, and have decided to focus on
> > using the jstl as the basis for my efforts.  it seems to provide exactly
> > what i needed, some basic, compatible tags to get started.
> > 
> > it is clear, however, that i'm going to have to write my own tags to get
> > any serious work done.
> > 
> > my question is this,  i figure that if i'm going to standardize on the
> > jstl, then it only makes sense to standardize on the EL stuff also, i
> > prefer its style to the scriplet thingies, and its less typing.  but,
> > i'm wondering what the preferred/recommended method is for doing this.
> > 
> > i see in the src dist for the reference jstl that there are a couple of
> > classes that look promising to use.  one is an interface
> > (ExpressionEvaluator) and then an implementing class
> > (ExpressionEvaluatorManager).  using it appears to be as simple as this
> > (from tag/el/core/ForEachTag.java):
> > 
> >   if( begin_ != null )
> >   {
> >     Object r = ExpressionEvaluatorManager.evaluate(
> >                   "begin", begin_, Integer.class, this, pageContext );
> >     if (r == null)
> >     {
> >       throw new NullAttributeException("forEach", "begin");
> >     }
> >     begin = ((Integer) r).intValue();
> >     validateBegin();
> >   }
> > 
> > it is acceptable to utilize this class in this manner for custom tags?
> > or is there a better/standard way.  i have been unable to find any docs
> > that talk about using the standard EL in your own tags, but if anyone
> > has any pointers, i would greatly appreciate it.
> > 
> > thanks,
> > 
> > --
> > 
> >     CraigL->Thx();
> >     Be Developer ID: 5852
> > 
> >   ------------------------------------------------------------------------
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> 
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-- 

    CraigL->Thx();
    Be Developer ID: 5852


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