JSP TAGS: tag reuse, setParent and findAncestorWithClass

[Justin Kennedy]

Hi,

I'm upgrading our tag library to Tomcat 5 and having problems. Note
that they were written back in JSP 1.1 and haven't changed for a few
years.

The problem looks like the tags are being cached and the setParent
isn't being called for each new "reuse". As a result the wrong tag is
returned from findAncestorWithClass when the WriteValueTag is re-used
in a different nested block. Maybe this is how the spec was designed
and I just don't know the right way to code the tags… Anyway here's
what the JSP page looks like (note: transacttag issues a call to the
database. Writevaluetag writes the value of a column from the data
returned from transacttag. If ‘transactId' isn't passed to
WriteValueTag, it will use the findAncestorWithClass to find the
enclosing IterateTag to determine the transactId):

<trans:transact id="uis" action="main_uis"/>
<logic:iterate transactId="uis" column="uiid">
<logic:equal value='<%=tmpuiid%>' column="uiid">
a - <trans:writeValue column="UI_NAME" /><br>
<transarameters id="params" scope="request">
<trans:addParameter parametersId="params" key="UIID"
value='<%= tmpuiid %>'/>
</transarameters>
<trans:transact id="ui" action="sub_uis" parametersId="params" />
<logic:exists transactId="ui" column="description">
<logic:iterate transactId="ui" column="ui_flowid">
#1 - <trans:writeValue column="UI_NAME" /><br>
#2 - <trans:writeValue transactId="ui"
column="FORM_NAME"/><br>
#3 - <trans:writeValue column="FORM_NAME"/><br>
</logic:iterate>
</logic:exists>
</logic:equal>
</logic:iterate>

The problems:
UI_NAME in #1 is a column from the first "uis" transactTag. The
writeValueTag prints out the value of this column but it shouldn't
behave this way because it's enclosed IterateTag has a different
"transactId". I put this here to demonstrate the problem
FORM_NAME in #3 is a column in the second transactTag of "ui". This
column value SHOULD be output (like it has always done) because the
enclosed iterateTag specifies the proper transactId, but this value is
not output because it's parent is set to the first IterateTag and not
the second, hence the different transactIds.

#2 works only because I'm explicitly setting the transactId.

The WriteValueTag extends the TagSupport class and everything is done
in the doStartTag event.

Please advise,
-Justin