Ref: Re: [Opensource] Really strange bug when using Expresso in Tomcat 4.1

[Michael Rimov]

>Michael,
>
>I found it!!


Excellant News. Thank you for the rundown.  Just to double-check, most of 
those tags should have SKIP_BODY in them, correct?

                                         -Mike



>in JSP 1.2(tomcat 4.1) the default behaviour for custom tags is to reuse
>them, which improves performance, whereas in JSP 1.1 (tomcat 4.0) it
>constructs a new object each time the tag is called.
>
>According to the guidelines, all the private invocation-specific state
>should be in the doStartTag() method rather than in the constructor, and
>AttributeTag has no doStartTag() method, therefore it doesn't get reset.
>
>Simply by adding the following lines to AttributeTag.java the problem was
>gone:
>
>...
>/**
>* Standard doStartTag.
>*
>* @return  int
>* @throws  javax.servlet.jsp.JspTagException
>*/
>public int doStartTag() throws JspTagException {
>    return EVAL_BODY_INCLUDE;
>}
>...
>
>
>
>Here are some docs about this:
>http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jasper-howto.html
>
>http://www.onjava.com/pub/a/onjava/2001/11/07/jsp12.html
>
>http://jakarta.apache.org/taglibs/guidelines.html
>
>
>I checked and this method is missing too in the following tags, but I don't
>know wether or not it's neccesary for them:
>
>Back
>ContentTag
>DBDescription
>LabelTag
>Login
>MessageUtil
>UserName
>ExpressoTagSupport
>ExpressoBodyTagSupport
>
>
>
>
>
>Thank you very much for your help!
>
>
>Best regards,
>
>Raul Davidovich
>
>
> >>At 06:57 AM 9/18/2003, you wrote:
> >>>I found out a very strange behaviour when running expresso on Tomcat
>4.1,
> >>>which doesn't come up in tomcat 4.0.
>
>
> >>Hi Raul!
>
> >>What you're hitting is a tag reuse problem.  The controller element being
> >>used is still reflecting the initial one even though through the reset of
> >>the tags before use in the next use of the tag.
>
> >>I thought this was fixed for 5.3, and POSSIBLY later versions of 5.0.X
> >>[maybe >.0.3??]  but I can't be sure.  I just remember coming across this
> >>and a fix posted by somebody on the list.
>
> >>What's your version you're encountering this.  We'll have to figure out
> >>what's not getting reset between instance uses.
>
> >>                                                                 -Mike
>
>
>
>
> >The symptom is OutputTags in JSP don't get refreshed when the transition
> >leads to the same page with updated outputs.
> >
> >I've tracked down the problem up to the level of AttributeTag. What
>happens
> >here is that because of some strange reason, the variable "oneElement" in
> >the AttirbuteTag object always points to the output object created the
> >first time the page was built, and it doesn't get updated the following
> >times, while all other references to this output object point now to the
> >new one (myOutput in MYController, and oneOutput in OutputTag).
> >
> >So for example we have page a.jsp, which shows the output of the state
> >promptAState from MyController.
> >This page has an "again" button which will lead to the AState of
> >MyController, and this state will give it's results again to promptAState,
> >who will show them in an output object, and prompt for a new value and
> >"again" or "ok".
> >
> >Let's say that the first time, the output was "123", and the second time
>it
> >was "456". In tomcat 4.0 this works fine, but in tomcat 4.1, it will still
> >show "123", no matter how many times I press "again". (I insist that the
> >new output object is created and filled up with the right values, and
> >OutputTag points to the right object)
> >
> >
> >Any clues?
> >
> >
> >Best regards
> >
> >
> >Raul Davidovich
> >
> >
> >
> >
> >_______________________________________________
> >Opensource mailing list
> >Opensource at jcorporate.com
> >http://mail.jcorporate.com/mailman/listinfo/opensource
> >Archives: http://mail.jcorporate.com/pipermail/opensource/
>
>
>_______________________________________________
>Opensource mailing list
>Opensource at jcorporate.com
>http://mail.jcorporate.com/mailman/listinfo/opensource
>Archives: http://mail.jcorporate.com/pipermail/opensource/
>
>
>_______________________________________________
>Opensource mailing list
>Opensource at jcorporate.com
>http://mail.jcorporate.com/mailman/listinfo/opensource
>Archives: http://mail.jcorporate.com/pipermail/opensource/