Right, that's just not gonna happen with JSTL's EL. Well, I suppose you could keep a "shadow" map that mapped values to keys, but that seems like a management headache as well as a bit of session bloat. With JSP 2.0, you could create an EL function to do it, but you're out of luck with JSP 1.2/JSTL 1.0. Even programmatically, there's no straightforward method for getting the key of a mapped value. You basically have to iterate through the entries looking for a mapping that contains a value equal to one you're holding. You may want to investigate writing a custom taglib for this if you really need this functionality in a JSP. Other options are to use a Filter or Servlet (or a controller component if you're using an MVC framework) to search for the key and then set it as a request attribute for the JSP to use.
Quoting Adrian Beech <[EMAIL PROTECTED]>: > G'day, > > Ummmmmm, this returns the value associated with the key... I need to do the > opposite whereby I have the value and I need it's key. > > Thanks. > AB > > -----Original Message----- > From: Tim Troy [mailto:[EMAIL PROTECTED] > Sent: Saturday, 9 October 2004 10:33 PM > To: [EMAIL PROTECTED] > Subject: FW: [JSTL] Retrieving the key from a LinkedMap for a known value? > > > I have a bean with a HashMap named errorCodes. To access a key using jstl, > I do the following: > > <c:out value="${bean.errorCodes['categoryId']}"></c:out> > > -----Original Message----- > From: Adrian Beech [mailto:[EMAIL PROTECTED] > Sent: Saturday, October 09, 2004 1:59 AM > To: 'Tag Libraries Users List' > Subject: [JSTL] Retrieving the key from a LinkedMap for a known value? > > > G'day all, > > Is it possible to retrieve the key from a LinkedMap for a known value using > the expression language syntax under JSTL 1.0? > > For example, I have a LinkedMap object which is being used to generate a > drop down with the <input:select .../> tag from the Input taglib. Apart > from needing the value selected by the user from the drop down I need to > pull the corresponding key for display purposes on the next page along in > the food chain. As I've already got the key/value pairs in a LinkedMap > within the session context I was hoping to merely say "well here is the > value from the drop down now give me the key which was used as the display > text for that drop down". > > Does this sort of make sense? > > AB -- Kris Schneider <mailto:[EMAIL PROTECTED]> D.O.Tech <http://www.dotech.com/> --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
