Juggle between jstl and jsp!

Question

I have a list of items and whose size is obtained by jstl as follows:
<c:set var="num" value="${fn:length(form.namesList)}"/>I have to find the number of blocks using jsp and I am trying as follows which is giving jspException.
<%int numCols = (int)Math.ceil( num / 10.0);%>Can anyone tell me the problem over here?
I need to use numCols to display my results using jstl as follows:
<c:forEach var="y" begin="${1}" end="${numCols }">
</c:forEach>Can juggle between jstl and jsp like this?

Answer 1

This depends on the version of JSP you are using:
If you are using JSP 2.0 (like Tomcat 5), make sure you have downloaded and installed JSTL 1.1 and set the web.xml up to use the Servlet 2.4 specs. Then the code you wrote should work.
If you are using JSP 1.x (like Tomcat 4 and below), make sure you have JSTL 1.0. Then you can only use EL (the Expression Language used to translate ${...} expressions) inside JSTL.
If you want to use EL inside your custome tags, look through the Apache Jakarta sight. Somewhere they have an ELExpression translator (a couple of classes actually - whose full names I forget). These classes will let you take the ${...} expressions in as strings, pass them through the translators and get the correct objects back out.
Or you could go a simpler root:
<mob:whatever object="test" name="newname" />
then in your custom tag:
  MyType test = (MyType)pageContext.findAttribute(object);
  test.setName(name);