Access variables between nested JSP tags

I would like to exchange information between two nested JSP tagx artifacts. To give an example:

list.jspx

<myNs:table data="${myTableData}">
    <myNs:column property="firstName" label="First Name"/>
    <myNs:column property="lastName" label="Last Name"/>
</myNs:table>

Now, the table.tagx is supposed to display the data columns as defined in the nested column tags. The question is how do I get access to the values of the property and label attributes of the nested column tags from the table tag. I tried jsp:directive.variable but that seems only to work to exchange information between a jsp and a tag, but not between nested tags.

Note, I would like to avoid using java backing objects for both the table and the column tags at all.

I would also like to know how I can access an attribute defined by a pa开发者_JS百科rent tag (in this example I would like to access the contents of the data attribute in table.tagx from column.tagx).

So it boils down to how can I access variables between nested JSP tags which are purely implemented through the tag definitions themselves (no Java TagHandler implementation desired)?

The idea is to share the data in request scope:

1. In myNs:table create a request scoped placeholder variable to hold the data (in your case you will need two of them: one for properties and another for labels):

   <c:set var="properties" scope="request" />
   <c:set var="labels" scope="request" />
   

2. Then invoke your column tags via <jsp:doBody /> so that columns could populate the placeholders.

3. In myNs:column populate the placeholders, remember to keep them in request scope:

   <c:choose>
     <c:when test="${empty properties}" scope="request">
       <c:set var="properties" value="${property}" scope="request" />
     </c:when>
     <c:otherwise>
       <c:set var="properties" value="${properties},${property}" scope="request" />
     </c:otherwise>
   </c:choose>
   

4. Now, after you invoked <jsp:doBody /> in your myNs:table you got the values populated, all you need is to split the string using comma as a separator and then do whatever you want:

   <table>
     <thead>
       <tr>
         <c:forTokens items="${labels}" delims="," var="label">
           <th><c:out value="${label}" /></th>
         </c:forTokens>
     </thead>
   </table>
   

P.S.: The credits go to Spring Roo guys, take a look at their table.tagx and column.tagx.