Jon,
http://jakarta.apache.org/velocity/ymtd/ymtd.html
I read your comparison of Turbine/Velocity and Struts/JSP and although you
state it your aim to be "fair and unbiased", I think you failed since most
of your examples, although sytanctically correct, were poor examples of the
use of Struts and Jsp. I only started getting into Jsp & Struts a couple of
weeks ago but below are my comments on your article. I also copy this to the
struts mailing list as I am sure more experienced people may be able to
comment better.
In your first example "Saying Hello" there is not need whatsoever in Jsp to
have any "out.println" statements. The example you gave could have been
coded in the following way:
<html>
<head><title>Hello</title></head>
<body>
<h1>
<% if (request.getParameter("name") == null) %>
Hello World
<% else %>
Hello, <% request.getParameter("name") %>
</h1>
</body></html>
On the subject of "Generation", I don't believe this is a big issue, since
1) its automatically handled by the servlet container and therefore not a
big issue to developers and 2) the performance issue is only relevant when
you change the application, its not like it happens every time you run the
jsp.
On the subject of "Error Handling", you are comparing Velocity only with
Jsp - the idea of Struts is that, it takes the need for Scriptlets out of
Jsp by providing custom tags (java classes) to deal with those situations.
What you quote here from Jason's books is only relevant to Scriptlets, not
well written Struts applications. The issues stated there are exactly why a
framework such as Struts was developed and an argument for using Struts.
Again in the section of "JavaBeans" you are not comparing like-with-like.
Velocity/Turbine will have the same issues of "Scope" that any Web
Application has and from what I see of your Velocity/Turbine example, you
have just hidden this from the Web Designer. The same can be done in a
Struts application with Struts tags rather than the "<jsp:useBean>" tag.
Again your quote from Jason's book relates solely to Jsp and is not a fair
comparison to Struts.
I'll ignore the sample app section, again its Jsp not Struts.
The "Taglibs" section is the first serious section which deals with Struts
and you start with cheap points about "cutting edge of a broken wheel" - so
tell me how is Velocity cutting edge then? - yet another scripting language
to handle presentation that a Web Designer needs to get to grips with. The
idea with Jsp/Struts is that it extends HTML in the same "style" to what Web
Designers are used to.
I would be the first to say the Struts documentation could be better but the
two examples that you listed from the Struts documentation were small
examples used to illustrate specific Struts features and not the best way to
develop Struts applications on the Model 2 architecture. The first example
using the <logic:equal> tag is poor because it encapsulates the "business
logic" (I know its simple) of the app in the presentation and therefore
shouldn't have been in the Jsp. Complex logic shouldn't be in the
presentation layer and so their use should be limited. The "if. . . .else"
logic of Velocity looks good to me, as a programmer, but I think a Web
Designer would be more at home with the Tag Style they are used to.
In your second example from the Struts document which uses a Scriptlet to
define an ArrayList - this has clearly been done to make the example simple
(a point I seem to remember being made in the document, though I couldn't
find the example again) - it is a break from the MVC architecture but its
not how Struts should be used, this collection would have been created in
the "logic" java end and put into scope ready for a Web Designer to use
through Struts tags - as simple or simpler than the Velocity example.
And finally - the example from "Jason Hunters" book which you say has been
entirely implemented as a Struts app - this is awful and is a complete abuse
of everything that Struts is about - why not get a decent Struts developer
(not me!) of giving you a good example - also where is the Velocity
equivalent for fair comparison - nowhere to be seen!
I was hoping for an article which would help me make an informed decision
but your portrayal of Struts didn't show it in the way it should be used or
explain what else it could do, such as Internationalization. I understand
(but not like) commercial software vendors going to any means to disparage a
competitors product but I am shocked that one Open Source project has done
it to another when they both come under the same Apache umbrella.
Niall
winmail.dat
