Rickard Öberg wrote:
>
> Hi!
>
> I'm trying to optimize my tag library, especially for the case where
> tags are used inside of iterating tags.
>
> Example:
> <x:iterate>
> <x:dostuff foo="bar"/>
> </x:iterate>
> --
> In the above case I want only one instance of the dostuff tag to be
> created, since I am doing things with the foo attribute whose value
> never changes (i.e. I compute things once in dostuff.setFoo() and want
> to skip it for all other iterations).
>
> According to the JSP spec this should work great. However, when I look
> in the generated JSP code (Tomcat 3.2 BTW), the dostuff tag is
> instantiated for each iteration! This means that I cannot do the above
> optimization. This adds a significant (and unnecessary) performance
> penalty!
>
According to to the spec, when a custom tag is closed out it falls out of
scope and the object instantiated for its tag class can be recycled.
But you can design your tags to do what you want.
There are two ways you could do this.
Split your x:dostuff tag into to tags like this:
<%-- The initstuff tag stores state information for the dostuff tag --%>
<x:initstuff>
<x:iterate>
<%-- The dostuff tag uses findAncestorWithClass() to get the parent
xinitstuff object --%>
<x:dostuff/>
</x:iterate>
</x:initstuff>
Another way is the following
<x:iterate>
<%-- the dostuff tag stores its state information as a PAGE_CONTEXT
attribute named "this" the first time through the loop. On the remaining
iterations it gets the state information from the PAGE_CONTEXT
attribute named "this". --%>
<x:dostuff id="this"/>
</x:iterate>
----------------------------------------------------------------------
Glenn Nielsen [EMAIL PROTECTED] | /* Spelin donut madder |
MOREnet System Programming | * if iz ina coment. |
Missouri Research and Education Network | */ |
----------------------------------------------------------------------
