Daniel Cricco wrote:
> Great!!!!
>
> You also not need the line
>
> <c:set var="table" value="${table}" scope="request"/>
> since
>
> <c:forEach>
>
> do it for you if you specify in:
>
> <c:forEach items="${tablesList}" var="table">
This is exactly correct.
> BTW:
> <c:set var="table" value="${table}" scope="request"/> is something like
Collection table;
> //put some data in table
> table=table;
>
> It is not an error but it should be interpreted as a warning in your
java compiler
No, this isn't really how it works. <c:set> sets the variable as an
attribute in one of the HTTP application scopes. So really your
pseudocode works like:
Collection someObject;
//put some data in someObject
request.setAttribute("table", someObject);
There's no object within the actual programming scope called table unless
you explicitly create one within a scriptlet. And you can stick things
into the attribute cache with the same name repeatedly and never get a
compiler warning or a run-time warning either for that matter. ALL of
these tags work on attributes. Where the attributes are stored depends on
the scope attribute. The default scope for <c:set> is page, while the
default scope for displaytag is request, so you would need to specify
scope for at least one of the tags for them to peacefully co-exist.
Laura, in response to your earlier post:
> <c:forEach items="${tablesList}" var="table">
> <% Enumeration<String> attributes = request.getAttributeNames();
> for(String attribute : attributes)
> {
> out.println(attribute + ": " + request.getAttribute(attribute) +
> "<br/>\n");
> }%>
> </c:forEach>
>
> doesn't work, I get error "Can only iterate over an array or an instance of
> Java.lang.iterable" and as I don't know this type I didn't go further in
trying but
> I will (Enumeration - is it from old Java versions? I only know enum)
Yeah, I was just typing that out, there's a couple of mistakes in there.
First, to get the Enumeration<String> from the request.getAttributeNames()
you'd need to cast it:
Enumeration<String> attributes = (Enumeration<String>)
request.getAttributeNames();
And even then you can't use for(:) with that. Which is an annoying thing
about Enumerations, but there you are. Anyways, the Enumeration class has
been in Java since the beginning in the java.util package. It's basically
not even comparable to enum except in the most facile way, so forget all
about that :)
The proper way to do what I was showing you is this:
Enumeration attributes = request.getAttributeNames();
while (attributes.hasMoreElements())
{
String attribute = (String) attributes.nextElement();
String value = request.getAttribute(attribute);
out.println(attribute + ": " + value + "<br/>\n");
}
This is a useful little snippet of debugging code to keep handy whenever
you're having trouble not finding something with a tag, such as in your
case. You can use various scopes by calling the getAttributeNames()
method from each object (request, session, application), or you can use a
handy method on the pageContext object:
pageContext.getAttributeNamesInScope(PageContext.PAGE_SCOPE)
pageContext.getAttributeNamesInScope(PageContext.REQUEST_SCOPE)
pageContext.getAttributeNamesInScope(PageContext.SESSION_SCOPE)
pageContext.getAttributeNamesInScope(PageContext.APPLICATION_SCOPE)
These each return Enumerations containing the attribute names for that
scope. There's a corresponding getAttribute() method too:
pageContext.getAttribute("name", PageContext.PAGE_SCOPE);
pageContext.getAttribute("name", PageContext.REQUEST_SCOPE);
pageContext.getAttribute("name", PageContext.SESSION_SCOPE);
pageContext.getAttribute("name", PageContext.APPLICATION_SCOPE);
--
Rick Herrick
[EMAIL PROTECTED]
I haven't got time for inner peace.
"No reasonable definition of reality could be expected to permit
this."--Albert Einstein, Boris Podolsky and Nathan Rosen in 1935
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