A tradeoff.
In JSP 1.1 there is a non-zero cost in invoking doBeforeBody():
scripting variables will be synchronized after every such invocation
even if the method is empty and does nothing. Since, as you pointed
out, actions done in doBeforeAction() can be achieved through a
combination of doInitBody() and doAfterBody() and in most cases
doAfterBody() is enough, we decided to remove doBeforeBody(). That also
has the result of reducing a bit the number of methods that need to be
implemented by a class (e.g. a JavaBean) to support BodyTag, but that is
secondary.
Hope this helps,
- eduard/o
[EMAIL PROTECTED] wrote:
>
> Hi guys,
>
> In page 106 of JSP 1.1 PR2 spec, there are two methods defined in the BodyTag
> Interface:
> doInitBody() and doAfterBody().
>
> doInitBody(): Invoked before the FIRST time the body is to evaluated .....
> <snip>.......
> doAfterBody(): Invoked after EVERY body evaluation ...... <snip>....
>
> My concern is this:
> I would have found it useful if there were a method doBeforeBody() defined.
> Is there a reason this method was not specified. The method only makes sense
> considering the existence of doAfterBody().
>
> I page 100 of JSP 1.1 PR1 spec, this method was specified in the Tag class. Why
> was this method
> removed from the spec?
>
> The reason I wanted this method is that I make certain scripting variables
> available to the body
> of the tag. The value of this variable is re-calculated at the beginning of
> every iteration of the body.
>
> Consider a loop tag.
>
> <custom:loop start="<%= startIndex%>" count="<%= count %>">
> </custom:loop>
>
> It would be useful for the tag body to know the current iteration of the loop.
> If there was a doBeforeBody(),
> I could set the value of the scripting variable in this method. Instead, I have
> to set the value for next iteration
> in the doAfterBody() method. Doing it in the doAfterBody works fine, but it
> just doesn't seem elegant.
>
> I am running on Windows NT, Orion Server version 0.7.9
>
> Thank you very much,
> Sharath Komarla
> PSDI
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