Chris Wilson wrote:
> here's a simple example of what i'm talking about. would one of your
> wizards please try this servlet and jsp page to see what i'm talking about?
> thanks very much!
>
I did some playing with this as well. It seems to be a Java API issue --
Map.Entry is an inner class, so apparently Java reflection APIs are not allowed
to call it's methods dynamically (the way that the Struts tags need to in order
to be generalized :-(.
As you noted, using mapEntry.getKey() and mapEntry.getValue() directly seems to
work, so we could cheat if need be -- but I would hate to start special casing
the code in <bean:write> (and all the other tags that can access properties) for
wierd situations like this ...
Craig
>
> i tried this on tomcat 3.2.1, jdk 1.3, win 2000
>
> ###### Begin TestServlet.java ######
>
> import javax.servlet.http.HttpServlet;
> import javax.servlet.http.HttpServletRequest;
> import javax.servlet.http.HttpServletResponse;
> import javax.servlet.ServletException;
> import java.util.HashMap;
> import java.io.IOException;
>
> public class TestServlet extends HttpServlet {
> public void doGet(HttpServletRequest req, HttpServletResponse res)
> throws ServletException, IOException {
> HashMap map = new HashMap();
> map.put("test", "hope this works");
> map.put("foo", "bar");
> req.setAttribute("map", map);
> getServletContext().getRequestDispatcher("/display.jsp").forward(
> req, res);
> }
> }
>
> ###### End TestServlet.java ######
>
> ###### Start display.jsp ######
>
> <%@ taglib uri="struts-logic.tld" prefix="logic" %>
> <%@ taglib uri="struts-bean.tld" prefix="bean" %>
> <html>
> <head>
> <title>display.jsp</title>
> </head>
>
> <body>
> <logic:iterate name="map" id="entry" scope="request"
> type="java.util.Map.Entry">
> <!-- i get an IllegalAccessException when running the following two
> lines -->
> <!-- delete the following two lines to elimate the
> IllegalAccessException -->
> <bean:write name="entry" property="key" scope="page" /> ->
> <bean:write name="entry" property="value" scope="page" /><br>
> <!-- why dosen't this work? -->
> <!-- end delete -->
>
> <!-- these two lines work! they don't throw an exception -->
> <!-- they are functionally equivelent to the above two lines right? -->
> <%= ((java.util.Map.Entry)pageContext.getAttribute("entry")).getKey() %> ->
> <%= ((java.util.Map.Entry)pageContext.getAttribute("entry")).getValue()
> %><br>
> </logic:iterate>
> </body>
> </html>
>
> ###### End display.jsp ######
>
> | chris wilson || web dev ||| [EMAIL PROTECTED] || | www.wondergeek.com |
> |
>
> > -----Original Message-----
> > From: Chris Wilson [mailto:[EMAIL PROTECTED]]
> > Sent: Thursday, January 04, 2001 10:46 AM
> > To: [EMAIL PROTECTED]
> > Subject: RE: Can I use a Map.Entry as a bean?
> >
> >
> > yes,
> >
> > i've included both taglib defs... in fact, the tags are working great.
> > it's only the write tag that's having a problem, and only when i
> > try to get
> > a property on a Map.Entry
> >
> > <bean:write name="subjectEntry" property="value" scope="page" /> // this
> > fails with an IllegalAccessException...
> >
> > ((java.util.Map.Entry)pageContext.getAttribute("subjectEntry)).get
> > Value() //
> > this works!
> >
> > if i use my own bean in the write tag, everything is dandy. it's just the
> > dang Map.Entry!
> >
> > | chris wilson || web dev ||| [EMAIL PROTECTED] || |
> > www.wondergeek.com |
> > |
> >
> > > -----Original Message-----
> > > From: Ted Husted [mailto:[EMAIL PROTECTED]]
> > > Sent: Thursday, January 04, 2001 10:11 AM
> > > To: Struts List
> > > Subject: Re: Can I use a Map.Entry as a bean?
> > >
> > >
> > > So, you've included the Struts bean tag library along with logic, yes?
> > >
> > > <%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
> > > <%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>
> > >
> > > You can get some weird and misleading error messages if you omit a
> > > taglibs you're using.
> > >
> > > The inner class shouldn't cause a problem, since the iterate tag is
> > > designed for that (an attribute or property of an attribute).
> > >
> > > For more troubleshooting, did you try setting the inner class as a
> > > standalone page attribute, to see if that works too?
> > >
> > > *********** REPLY SEPARATOR ***********
> > >
> > > On 1/4/2001 at 9:17 AM Chris Wilson wrote:
> > >
> > > hello,
> > >
> > > sorry to post this similar message again, but i'm really stumped...
> > >
> > > i've run into a problem however trying to use the iterate tag with a
> > > TreeMap
> > > and the write tag... here's a snippet of my code:
> > >
> > > <logic:iterate name="subjects" id="subjectEntry" scope="request"
> > > type="java.util.Map.Entry">
> > > // subjects is a TreeMap in the request object... no problem there
> > > // it's my understanding that when the iterate tag is used with a map,
> > > the
> > > // iterator is on the Set of Map.Entries returned by Map.entitySet(),
> > > // therefore the object exposed as subjectEntry should be a
> > > java.util.Map.Entry
> > >
> > > <bean:write name="subjectEntry" property="value" scope="page" />
> > > // this is where i get an IllegalAccessException attempting to access
> > > the
> > > //property value of subjectEntry, even though there is a getValue()
> > > method
> > > in the
> > > //api...
> > >
> > > </logic:iterate>
> > >
> > > just for fun, i replaced the write tag above with the following
> > > scriptlet
> > > which i believe is logically equivalent:
> > > <%=
> > > ((java.util.Map.Entry)pageContext.getAttribute("subjectEntry)).getValue(
> > > )
> > > %>
> > >
> > > and that works! of course, i could simply use this scriptlet and my
> > > problem
> > > would be solved, but i'd like to use only taglibs if possible and it
> > > seems
> > > to me that the <bean:write> tag should do the same thing...
> > >
> > > will <bean:write> only work on "bean-like" objects that are public? in
> > > this
> > > case the object implementing the Map.Entry interface is an inner class
> > > in
> > > TreeMap. is that causing the problem?
> > >
> > > what am i missing? thanks for any help!
> > >
> > > cheerio,
> > > chris
> > >
> > > | chris wilson || web dev ||| [EMAIL PROTECTED] || |
> > > www.wondergeek.com |
> > > |
> > >
> > >
> > >
> > >
> >
> >
