Based on Josh's comment, I thought a bit more about this issue, and looked
at the finalized JSP 1.2 specification. Although Sun still has one example,
which uses a shortname ("myPRlibrary"), I noticed something that others may
find interesting. Since in JSP 1.2, the emphasis seems to be to recommend
making JSP pages into well-formed XML documents. The spec shows an example
of multiple taglib URIs in both standard JSP syntax and the recommended XML
syntax:
<html>
<title>positiveTagLib</title>
<body>
<%@ taglib uri="http://java.apache.org/tomcat/examples-taglib"; prefix="eg"
%>
<%@ taglib uri="/tomcat/taglib" prefix="test" %>
<%@ taglib uri="WEB-INF/tlds/my.tld" prefix="temp" %>
<eg:test toBrowser="true" att1="Working">
Positive Test taglib directive </eg:test>
</body>
</html>
XML VIEW OF JSP PAGE:
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page";
xmlns:eg="http://java.apache.org/tomcat/examples-taglib";
xmlns:test="urn:jsptld:/tomcat/taglib"
xmlns:temp="urn:jsptld:/WEB-INF/tlds/my.tld"
version="1.2">
<jsp:text><![CDATA[<html>
<title>positiveTagLig</title>
<body>
Notice that if you don't use the more common URL-like syntax, it seems that
you're required to add "urn:" to the xmlns definition. So, while it may be
easier to use a short, symbolic name, it may make sense to use the XML
namespace approach with the usual URL approach, just to make it simpler for
developers to not have to remember adding that extra part. I also see that
there's a version setting, so the Jakarta approach of appending a version to
the end of the URI is not necessary anymore. So, in the end, I'm thinking
that the URL approach may make the most sense. Also, for XML developers, it
would be consistent with their expectations.
Steve
> -----Original Message-----
> From: Josh Partlow [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, October 31, 2001 9:51 AM
> To: [EMAIL PROTECTED]
> Subject: Re: taglib directive URIs -- short names?
>
>
> Steve Bang wrote:
>
> > According to the JSP 1.1 specs, the description of the
> <taglib-uri> setting
> > can be a short name. In both the Sun spec and in WebLogic
> docs, they give
> > examples of using short names, such as "myPRlibrary" (in
> the JSP 1.1 specs)
> > and "myTLD" (in WebLogic docs). And, Hans uses
> "/orataglibs" (or something
> > similar) for the tags in his book. Sometimes, shortened
> names have a
> > forward-slash in front of them, other times they don't.
> And, yes, I've read
> > the specs and the errata, and Hans' book. What I'm
> surprised at is the
> > amount of disagreement, or at least confusion. I'm finding
> about the right
> > approach is on such a seemingly simple topic. A taglib URI
> can be a URL
> > (such as, Jakarta's approach,
> > "http://jakarta.apache.org/taglibs/<tagLibName>") or a
> relative URL (I've
> > seen many using "/WEB-INF/tlds/<taglibname>.tld"), or even
> a short symbolic
> > name (like "TagLib"). But, here's what I don't get -- most
> of the time,
> > when a URL is used, it doesn't actually point to any file
> at the specified
> > address. Instead, it's only purpose seems to be as a way
> to help guarantee
> > a unique name -- it really doesn't matter what it is (it's
> only the unique
> > combination of characters that matter). So, if this is the
> real purpose, as
> > a way to create a unique name -- essentially a symbolic name, then a
> > shortened name makes more sense to me, if it seems to be
> unique. The "URL
> > (but not actually a real URL)" approach is clever in some
> regards, but
> > introduces misconceptions to naive users about what it
> represents. Today,
> > someone at work told me that they thought that if he was
> using a laptop that
> > wasn't connected to the Internet, they wouldn't be able to
> access this file,
> > so therefore they thought the taglib directive would fail.
> As a result, I'm
> > arguing that a symbolic name that is unique, such as
> myUniqueNameTLD or
> > something like that, is possibly the best approach. I've
> even joked that
> > using a URL (with your company name in it) may be more
> likely a problem than
> > a short name (and less flexible) in that a company might
> get acquired, and
> > the acquiring company could end up insisting that the URI
> be changed.
> >
> > So, I'm interested in hearing some opinions about why the
> URL approach won
> > in your designs -- was it just that it seemed what everyone
> else was doing?
> > Or, do some application servers cannot handle shortnames?
> Or, why did you
> > pick a shortname -- weren't you worried about the uniqueness issue?
> >
> > Steve
> >
> >
> ==============================================================
> =============
>
>
> Hi Steve,
>
> I assumed (and this is just me guessing), that it had to do with
> XML namespaces. ( http:
//www.w3.org/TR/1999/REC-xml-names-19990114/ )
> This is how XML Namespaces are set, and jsp:getProperty or
> custom:myAction are the same syntax used in XML to separate different
> sets of elements (prefix:elementName). I'm assuming that the
> <% taglib
> %> directive is JSP's way of identifying namespaces in any document,
> given that most aren't going to be XML, and that containers parse jsp
> pages as they would an XML doc, in which case, jsp: tags and then
> custom: tags can be appropriately earmarked for the classes that run
> them. Given that you want XML documents to be clear anywhere, using a
> URI allows you to pick a reasonably unique identifier
> (organization/department/project whatever) without having to
> consult the
> rest of the world. Or perhaps they were just borrowing the idea of
> namespaces and used the same syntax?
> Anyway, that was my guess. Maybe someone who actually
> knows will
> chime in now. :)
>
> Josh
>
> --
>
> ------------------------
> Josh Partlow
> [EMAIL PROTECTED]
>
> ==============================================================
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