How can I c:set an int in my JSP?

[John M. Gabriele]

I want to use an int (or Integer) in my JSP to act much like a counter inside a <c:forEach> loop. I'm trying to do something like this:

<c:set var="counter" value="0" />
<c:forEach ...>
    <%-- ... --%>
 
    <c:set var="${counter}" value="${counter + 1}" /> <%-- line 49 --%>
 
    <c:if test=${something_condition}>
        <p>Whoops. Starting over.</p><c:set var="${counter}" value="${0}" />
    </c:if>
</c:forEach>

But it's not working. I'm getting an exception:

"foo.jsp(49,4) According to TLD or attribute directive in tag file, attribute var does not accept any expressions"

Where line 49 is noted in the above code snippet.

How can I use a simple int in my JSP?

[Bear Bibeault]

var doesn't accept expressions. Your problem really has nothing to do with using integers. If you want to set a variable named counter the syntax would be...

<c:set var="counter" ...  

That said, would perhaps the following form of forEach achieve your goal better?

  
<c:forEach begin="1" end="100" var="counter">
  The counter is ${counter}.
</c:forEach>
 

[ August 31, 2005: Message edited by: Bear Bibeault ]

[John M. Gabriele]

Za! How did I miss that... Thanks for the reply Bear.

Also thanks for the alternate suggestion. In my case though, it's a bit more complicated, and I need my <c:forEach> index for something else. If you're interested,.. I've got this big list of items I'm looping through:

for example, an alphabetized list of names:

Alex
Andreas
Andy
{... bunch more A's ...}
Barry
Bear
Brandon
{... bunch more B's ...}
Charlie
{etc...}

and the page I'm rendering has a fixed number of columns of text to place those items in -- that is, say, 4 columns for each letter. After we're done with the A's, put in a <div> and move onto the B's. And so on.

The "counter" variable is there to tell me how many items I've written in a given column (i.e. "you've written 4 A's so far") -- when it hits some predetermined number (like, say, 5 items for this column), extra logic comes in to end the current column and start a new one.

Thanks again,
---John
[ August 31, 2005: Message edited by: John M. Gabriele ]

[Bear Bibeault]

Ah, so you need to maintain your own internal counter. That's cool.

[Stefan Evans]

Did you consider the varStatus attribute?
That keeps a record of the count for you ( as well as a few other things)

<c:set var="numPerColumn" value="5"/>
<c:forEach var="name" items="${nameList}" varStatus="status">
  <c:out value="${name}"/>
  <c:if test="${status.count % numPerColumn == 0}">
    // break column <br>
  </c:if>
</c:forEach>

[John M. Gabriele]

> Did you consider the varStatus attribute?

Hi Stefan. I'd used varStatus in the past to tell whether I was at the last iteration ( <c:if test="${status.last}"> ), but forgot that I could also get a count from it. Thanks. Incidentally, I notice from reading some docs that status.count gives you a 1-based, not 0-based, count.
[ September 01, 2005: Message edited by: John M. Gabriele ]

[Daniel Rhoades]

BTW - The index attribute of a varStatus variable also gives you the current increment