how to overwrite a request param?

[Tudor Raneti]

I'm doing something like this:

  <c:if test="${empty param.min_line}">
	<c:set var="min_lines" value="0" scope="request"></c:set></c:if>
<c:if test="${empty param.max_line}">
	<c:set var="max_lines" value="${param.lineCount}" scope="request"></c:set></c:if>
<c:if test="${param.min_line > param.max_line}">
	<c:set var="temp" value="${param.max_lines}" scope="session"></c:set>
	<c:set var="max_lines" value="${param.min_lines}" scope="request"></c:set>
	<c:set var="min_lines" value="${param.temp}" scope="request"></c:set></c:if>  

Which doesn't work, how i would properly write this in JSP (avoiding a scriptlet if possible, if not, a scriptlet is ok too).

[swapnl patil]

can you please explain it briefly what you want do ?

[Tudor Raneti]

I thought it's obvious from the code, i'm trying to do the following, but rewriting the params of request to not create more variables than necessary:

  String min_line = request.getParameter("min_line");
		String max_line = request.getParameter("max_line");
		String add_sums = request.getParameter("add_sums"), sums;
		boolean show_sums;
		/*** variables ***/
		if (min_line == null || min_line.equals(""))
			min_line = "0";
		if (max_line == null || max_line.equals(""))
			max_line = request.getParameter("max_lines");
		if (Integer.parseInt(min_line) > Integer.parseInt(max_line)) {
			String temp = max_line;
			max_line = min_line;
			min_line = temp;
		}  

[Ra Re]

Let's see if this is the answer to your question.

No, you can not override the request parameters values neither reuse these parameters as variables. When you use the c:set tag with the attribute scope="request" you are setting request attributes and not parameters. As a proof, we know that a JSP "becomes" a Servlet, so check the ServletRequest API in this link http://java.sun.com/j2ee/1.4/docs/api/javax/servlet/ServletRequest.html

There, you will see the public methods getParameter() but no setParameter(), instead, there exist setAtribute() and getAtribute, that is what you are really doing in the code you posted inside the first message.

[Tudor Raneti]

I feared as much, thank you.

[Bear Bibeault]

Tudor Andrei Raneti wrote:I thought it's obvious from the code

Nothing is ever "obvious from the code". In the future please be sure to clearly explain what you are trying to accomplish.

[Tudor Raneti]

Bear Bibeault wrote:

Tudor Andrei Raneti wrote:I thought it's obvious from the code

Nothing is ever "obvious from the code". In the future please be sure to clearly explain what you are trying to accomplish.

The question is only obvious to the answerer. Thus the name of the topic too. I find that people who don't care to answer a question also find the question meaningless, hence not obvious. And an answer has been given, thanks for sharing your opinion though.

EDIT1: I wonder if reflection can do anything to the request object, AFAIK it can, not gonna try it though if i can avoid it.