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Re: Conditional formatting elements of a collection in c:forEach

by Martin Cooper-2 :: Rate this Message:

On Wed, Feb 11, 2009 at 8:53 AM, Rashmi <rashmi.sub@...> wrote:

> Hello everyone,
>
> I'm trying to display a list of items in a collection using JSTL.
>
> Each item in the collection has x, y, z and id variables.
>
> The user can choose whether he wants the display order (of the items
> in the collection) to be
>
> 1) x y z
> 2) z y x
>
> As far as I know the display ordering can be accomplished in two ways:
> 1) as shown in the code snippet below, create two different loops for
> each display format. The drawback with this approach is that a lot of
> the common stuff is duplicated between the two loops.
>
> 2) Have a c:choose , selection within a single loop, which decides
> between the two formats. The drawback is that the the same condition
> checking repeats for each loop iteration.
>
> Is there a way to set the formatting outside the loop , and use that
> format in the loop to address the two drawbacks above.

Assuming you have a resource bundle around somewhere, add two format strings
to the bundle, one for each of your two display orders; use a condition
('when', 'if' or whatever) to set a variable with the appropriate key; then
use that variable to specify the key to <fmt:message> within your loop.

--
Martin Cooper

> <%@ page contentType="text/html;charset=UTF-8" language="java" %>
> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
> <html>
> <head>
> <title></title>
> </head>
> <body>
>
> <c:choose>
> <c:when test="${param.listBy == 'xFirst' }">
> <c:forEach var="item" items="${requestScope.items}">
> ${item.x} ${item.y} ${item.z}
> <a href="/show?id=${item.id}">show item</a>
> <a href="/edit?id=${item.id}">edit item</a>
> <a href="/delete?id=${item.id}">delete item</a>
> </c:forEach>
> </c:when>
> <c:otherwise>
> <c:forEach var="item" items="${requestScope.items}">
> ${item.z} ${item.y} ${item.x}
> <a href="/show?id=${item.id}">show item</a>
> <a href="/edit?id=${item.id}">edit item</a>
> <a href="/delete?id=${item.id}">delete item</a>
> </c:forEach>
> </c:otherwise>
> </c:choose>
> </body>
> </html>
>
> Any input is appreciated.
>
> -Rashmi
>
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