Recursive custom tag: different behaviour in WinXP and Linux

Question

Hi all,
I've a strange behaviour on a web application for which I developed a custom tag to render a tree structure.
This tag take in input an object representing the tree with all its nodes, and render every node, calling hitself recursively for every child of every node.
This tag is used inside a jsp.
I deployed my webapp on JBoss in a WinXP Pro environment, and everything is ok. Then I deployed the same webapp on JBoss in a Linux Env, and the call to the custom tag... doesn't write anything (with the same input).
Used jdk are 1.6.0_10 on WinXP and 1.6.0_7 on Linux (an OpenSuse professional distribution). JBoss is 4.2 (I did tests with JBoss 4.2.2 and 4.2.3).
Here is a sample code of my tag (file outree.tag):
<%@ tag language="java" pageEncoding="UTF-8" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib uri="http://jakarta.apache.org/taglibs/log-1.0" prefix="log" %>
*<%@ taglib prefix="ousel" tagdir="/WEB-INF/tags/ouselector" %>*
<%@ attribute name="subtree"
          required="true"
          type="my.webapp.TreeObject" %>
<%@ attribute name="subroot_index" required="true" type="java.lang.Integer"%>
<log:debug category="my.webapp.ousearch.taglib" message="Tag library called, starting operations..." />
<c:if test="${not empty subtree.children}">
     <c:set var="next_subtree_index" value="${subroot_index + 1}"/>
     <ul class="subtree" id="subtree-${subroot_index}">
     <log:debug category="${logcategory}" message="We have children, calling recursively tag library on them (next subtree index: ${next_subtree_index})..." />
     <c:forEach var="currentOUChild" items="${subtree.children}">
          *<ousel:outree subtree="${currentOUChild}" subroot_index="${next_subtree_index}"/>*
          <c:set var="next_subtree_index" value="${next_subtree_index + 1}"/>
     </c:forEach>
     </ul>
</c:if>
</li>The TreeObject contains a list of children that can contain other children and so on. On every child, I call recursively my custom tag to render with a set of nested <ul> elements the entire tree structure.
Here the call from the jsp:
<%@ taglib uri="http://jakarta.apache.org/taglibs/log-1.0" prefix="log" %>
*<%@ taglib prefix="ousel" tagdir="/WEB-INF/tags/ouselector" %>*
<log:debug category="${logcategory}" message="Building subtree ${ouSubtree} HTML structure..." />
*<ousel:outree subtree="${ouSubtree}" subroot_index="1"/>*
<log:debug category="${logcategory}" message="Subtree ${ouSubtree} HTML structure built" />
...Jakarta log taglibs is used to log the value of the parameter passed to the custom tag. In the Linux env I see that the passed object is not empty (it couldn't be null because the tag enforce it as a mandatory value).
Any idea?

Answer 1

I have found a workaround.
Simply substitute the recursive invocation, with an import of a jsp that will call the custom tag.
Note: You have to set your needed variable in request to make it visible to the jsp
<%@ tag language="java" pageEncoding="UTF-8" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib uri="http://jakarta.apache.org/taglibs/log-1.0" prefix="log" %>
<%@ attribute name="subtree"
          required="true"
          type="my.webapp.TreeObject" %>
<%@ attribute name="subroot_index" required="true" type="java.lang.Integer"%>
<log:debug category="my.webapp.ousearch.taglib" message="Tag library called, starting operations..." />
<c:if test="${not empty subtree.children}">
     <c:set var="next_subtree_index" value="${subroot_index + 1}"/>
     <ul class="subtree" id="subtree-${subroot_index}">
     <log:debug category="${logcategory}" message="We have children, calling recursively tag library on them (next subtree index: ${next_subtree_index})..." />
     <c:forEach var="currentOUChild" items="${subtree.children}">
                *<c:set var="_currentOUChild" value="${currentOUChild}" scope="request"/>*
                *<c:set var="_next_subtree_index" value="${next_subtree_index}" scope="request"/>*
          *<c:import url="/WEB-INF/tags/outtree.jsp"/>*
          <c:set var="next_subtree_index" value="${next_subtree_index + 1}"/>
     </c:forEach>
     </ul>
</c:if>
</li>Here is the imported jsp (outtree.jsp):
<%@ taglib prefix="ousel" tagdir="/WEB-INF/tags/ouselector" %>
<ousel:outree subtree="${_currentOUChild}" subroot_index="${_next_subtree_index}"/>