thanks for the explaination.
-will
Craig R. McClanahan writes:
>
>
> On Thu, 21 Jun 2001, William Shulman wrote:
>
> >
> > thanks Craig-
> >
> > I may be appealing to the wrong crowd (as I expect this stuff is all
> > part of the Servlet spec), but this somehow seems to be less modular
> > than I would like. It seems that the spirit or .war files is to be an
> > extension of the .jar file concept, generalized to entire j2ee
> > applications. When I obtain a .jar file for classes I would like to
> > use -- all I need to do is place that .jar file in my CLASSPATH and I
> > can use the classes. The analogy does not seem to fully carry over
> > into .war files. Would it not be better if I was able to package my
> > entrire application and supporting resources (html, xml, tld,
> > etc.. files) and have the servlet or j2ee system know how to access
> > all of those resources in a generic way, similar to the approach with
> > .jar files and classes? It seems that the current approach only goes
> > half way -- I can introduce a .war file and have the servlet container
> > interpret its structure in some ways (making a context, recognizing
> > the docroot, etc), but not in other ways (allowing my jsp files to
> > import or declare taglibs contained in the .war file, or recognize classes)
> >
>
> Well, you've certainly got most of the "self contained" stuff you are
> after:
> * Want to use a JAR file in your app? Stick it into /WEB-INF/lib
> and it is automatically available to you.
> * Want to access a static resource in your app? Use
> ServletContext.getResource() and you don't have to care how the
> servlet container deals with it.
> * Want to change the context path of your app? The details of how
> to do this vary by servlet container, but it's trivially easy
> (especially with Struts) to make your application independent
> of what the actual context path is.
> * Want to us a tag library? Somehow, you've got to create a mapping
> from the URI used in your pages to the corresponding TLDs. There
> are a variety of ways to do this, but I've found that explicitly
> referencing TLDs in the WEB-INF directory is the least confusing.
>
> > Is there some design reason for this that I do not understand? It
> > seems things could be architected such that the steps you outline
> > below are not needed.
> >
>
> For the separate TLD files themselves, there's a spec-related issue that
> caused this approach.
>
> The JSP 1.1 spec defines the concept of a tag library that is encapsulated
> in a single JAR file (including the TLD, which you placed at the
> META-INF/tablib.tld entry. Thus, you could just drop a tab library into
> your WEB-INF/lib directory, create a URI for it in web.xml, and go.
>
> Now, originally, Struts only had one tag library, so this strategy was
> quite useful -- stick the "struts.tld" file into struts.jar, and
> everything was fine. However, Struts now has four tag libraries (and the
> number is likely to grow in the future). But you cannot have more than
> one encapsulated TLD in a single JAR file in JSP 1.1 -- and separating
> struts.jar into five JAR files doesn't really help anything.
>
> In JSP 1.2, this changes -- you'll be able to to encapsulate all of the
> Struts tag libraries in struts.jar and dispense with the separate TLD
> files. But, until JSP 1.2 containers are widely deployed, we're stuck
> with the 1.1 restrictions.
>
> But the bottom line is that the architecture of web applications is
> defined by the servlet spec. Therefore, Struts has to live within those
> rules, just like any other web application or framework based on servlets
> will have to.
>
> > -will
> >
> >
>
> Craig
>
>
