Quoting David Geary ([EMAIL PROTECTED]):
> Hi Justin,
>
> I've been following this thread, and I've even looked at the WebMacro Web site, but
> I still have no idea what the advantages of WebMacro are over JSP. You seem to
> imply that JSP has shortcomings which WebMacro addresses, but I don't understand
> what the shortcomings are or how they are addressed by WebMacro.
>
> Care to elaborate?
It's very simple. WebMacro, or any other decent template system such
as FreeMarker (so you know I'm not just plugging my own product),
enforces a separation of concerns that I view as fundamental to
web development:
HTML/script on the front in the template (view)
+
100% pure Java servlet on the back controlling the web session
+
Business model implementing the business logic
This way of organizing things is generally called "Model/View/Controller".
In a tempalte system like WebMacro or FreeMarker, this amounts to the
only sensible way to think about your application. The architecture
enforces it, pushing you in the right direction.
JSP does not offer very good support for this design.
The most natural thing to do in a .jsp file is lump it all together
in one big chunk. That's what the language encourages you to do.
People who are a bit more savvy will move as much of the business logic
as possible into Java beans, thus getting a two level separation of
concerns. You're encouraged to do this in Sun's documentation, though
most .jsp code I've seen in my consulting practices doesn't really
work this way.
Where things really get nasty is if you try and get the full three
level separation out of your JSP application. You will find yourself
sorely tempted to mix session logic with presentation logic in a
single .JSP file. JSP offers almost no help in trying to resolve
this, and you are more or less on your own--having to remember this
fundamentally important design decision every time you write any
line of code anywhere.
The consequence is that nobody ever manages to pull this off. There
always winds up being some mixing of session logic with presentation
logic in JSP--it just slips in there, eventually.
This is bad. You really do need architectural support for your designs
from your tools.
By analogy, think of the "private", "protected", and "public" keywords
in the Java language. They impost restrictions on you, and stop you from
getting the information you want when and where you want it. If you
marked something "private" but you need to access it somewhere else,
you have to make a design decision. Java forces that on you. This
restrictive behavior is a GOOD THING because it forces good design
on you.
C programmers retort that they are such good programmers that they don't
need annoying restrictions from the language--they can just remember
what methods are supposed to be private, and not call them.
That position is fairly well refuted. Programmers make mistakes. You
need support from your tools to enforce your design.
WebMacro, and other similar products, give you that support. JSP does not.
Many people see the value in what I'm writing here. Probably by and large
WebMacro supporters tend to be a bit more experienced than everyone else:
people who have been around long enough to realize the importance of
these kinds of issues.
I think this is why WebMacro was recently selected as one of the best
three products of 1999 by the Java Report. (Current issue).
Justin
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