Hi,
I'm not sure too whether what you call Model ++2 would qualify as a new
model, as generating the JSP manually or from a XML file at design time
doesn't introduce a new element in your model 2 arquitecture. I'd vote
for Model 3(Model 2++) as a new one because it's not an extension of the
JSP model. In our first application we are not using JSP at all(we get
it from PL/SQL) and you might generate the XML directly from a servlet,
a WebMacro template... but anyway, the name is not important as long as
we all understand each other.
Regarding Model ++2, I've been thinking about it to see if we could also
use it (I don't enjoy adding layers for the sake of it :) ) and I've
come across some doubts that some of you might help me understand.
.- As disadvantages, I'd add that is JSP dependent and you don't really
get a clean separation of business logic/UI or at least as clean as
Model 3. If the Web Designer has to change something in the UI, he has
to change the xslt sheet and then ask technical people to re-generate
all the JSP pages affected by the change, doesn't he? You cannot change
the JSP's direclty, otherwise you'd loose the changes when you
re-generated the JSP's.
Let's see if I get the whole process with a very small sample
1.- You give the XML file to the designer
<Customer
Name="John Doe">
<Account ID="01" Balance="1230$">
<Account ID="02" Balance="-50$">
</Customer>
2.- The designer wants to produce the following output
<table>
<tr><td>Name:</td><td>John Doe</td></tr>
<tr><td>Account 01</td><td>12030$</td></tr>
<tr><td>Account 02</td><td bgcolor="red">-50$</td></tr>
</table>
3.- So he produces this XSLT
<xsl:template match="Customer">
<table>
<tr><td>Name:</td><td><xsl:value-of select="@Name" /></td></tr>
<xsl:apply-templates select="Account" />
</table>
</xsl:template>
<xsl:template match="Account">
<tr>
<td>Account <xsl:value-of select="@ID" /></td>
<td>
<xsl:if test="@Balance<0">
<xsl:attribute name="bgcolor">red</xsl:attribute>
</xsl:if>
<xsl:value-of select="@Balance" />
</td>
</tr>
</xsl:template>
4.- The JSP you would like to produce would be something like..
<table>
<jsp:useBean id="theCustomer" scope="request" class="Customer" />
<tr><td>Name:</td><td><jsp:getProperty name="theCustomer"
property="name" /></td></tr>
<% for( Enumeration e = theCustomer.getAccounts();
e.hasMoreElements;
)
{
Account theAccount = (Account) e.nextElement();
%>
<tr>
<td>Account <%= theAccount.getID() %></td>
<td
<%
if(theAccount.getBalance()<0)
{
<%
bgcolor="red"
%>
}
%>
><%= theAccount.getBalance() %></td>
</tr>
</table>
I don't see how you could get easily number 4 from 2 and 3. I get it for
simple cases where you might substitute the real name of the customer in
the XML file for <%= theCustomer.getName %> etc... but how about loops
and conditions? Do technical people have to refine the generated JSPs?
Or have I misunderstood the whole process?
Thanks
Dan
-------------------------------------------
Daniel Lopez Janariz ([EMAIL PROTECTED])
Web Services
Computer Center
Balearic Islands University
-------------------------------------------
Mike Van Riper wrote:
>
> Lee,
>
> It sounds like what you are doing is quite similar to our approach (using
> XSLT at design-time to generate JSP files). I agree with your assessment of
> the two variants for applying XSLT to the JSP Model 2 architecture. I'm not
> sure it qualifies as a whole new model though.
>
> <Bad Joke>
> How about:
> JSP Model ++2 (for XSLT preprocessing input XML to produce the JSP)
> versus
> JSP Model 2++ (for XSLT postprocessing output XML from JSP execution)
> </Bad Joke>
>
> - Mike Van Riper
> [EMAIL PROTECTED]
>
> > -----Original Message-----
> > From: Lee Elenbaas [mailto:[EMAIL PROTECTED]]
> > Sent: Tuesday, May 09, 2000 2:31 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Model 2 & 3 Architecture
> >
> >
> > What i have learned is from listening in this list.
> > Model 2 is setting a single entrance servlet to all your
> > JSPs. that servlet
> > performs common tasks like ID user and secuity tests and then
> > forwards the
> > request to the appropriate JSP/servlet, that JSP/Servlet jenerates the
> > HTML/content that the user sees
> >
> > Model 3 adds another layer of XML. There are two variations:
> > JSP/Servlet generates XML, that XML gows through XSLT (usually in the
> > server) to what the user sees.
> > The other approach (and the one we are testing in our
> > company) is XML that
> > are trasformed through XSLT to JSP pages, those JSP pages generate the
> > HTML/content that the user sees.
> >
> > Both variations added a level of seperation between the UI
> > design and the
> > java code.
> > The 1st variation has the added advantage of being more
> > client responsive.
> > This means you can generate using the same JSP and XML different views
> > according to the user platform: browser, WAP device...
> > The 2nd variation has the advantage of removing the XSLT
> > overhead from the
> > runtime. (and to my opinion it can also provide what the 1st variation
> > provides, but with more jenerated JSPs)
> >
> > lee
> >
> > Lee Elenbaas
> > ViryaNet
> > [EMAIL PROTECTED]
> >
> > -----Original Message-----
> > From: A mailing list about Java Server Pages specification
> > and reference
> > [mailto:[EMAIL PROTECTED]]On Behalf Of Germ�n L�pez Castro
> > Sent: Tuesday, May 09, 2000 11:09 AM
> > To: [EMAIL PROTECTED]
> > Subject: Model 2 & 3 Architecture
> >
> >
> > Hi-u-all.
> >
> > I think I've got a black hole in my acknoledgement, but... could
> > anyone explain me what architecture 2 & 3 are exactly and where can I
> > get further information?
> >
> > Thanxalot.
===========================================================================
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
