I use Struts for MVC web applications. http://jakarta.apache.org/struts
-Chris > -----Original Message----- > From: Alex Muc [mailto:[EMAIL PROTECTED]] > Sent: Saturday, October 12, 2002 11:09 AM > To: Tomcat Users List > Subject: Re: Defining methods in JSP pages > > > Yeah, that thought hit me last night as well (just after I sent the > message of course:). I was thinking more about the possibility of doing > the call from some other JSP page as well. > > Do you use these features? Do you have a prefered place for display > related functions (model/view/controller/other)? > > Alex. > > Chris Means wrote: > > >Alex, > > > >Are you aware that you could simply call the method that you defined > >directly in the JSP body? > > > ><%! > > public String getTitle(HttpServletRequest request) { > > String id = request.getParameter("id"); > > return "id: " + id; > > } > >%> > > > ><% > > String title = getTitle (request) ; > > > > out.write (title) ; > >%> > > > >-Chris > > > > > > > >>-----Original Message----- > >>From: Alex Muc [mailto:[EMAIL PROTECTED]] > >>Sent: Saturday, October 12, 2002 12:55 AM > >>To: [EMAIL PROTECTED] > >>Subject: Defining methods in JSP pages > >> > >> > >>Hi, > >> > >>I've been using JSPs for quite a while now and have been trying to find > >>better ways to do various things. One of the features of JSPs that I > >>stumbled on a while ago was the ability to define methods in JSPs and to > >>be able to call those methods from within the page using Java Reflection > >>mechanisms. This works relatively well (see example below), except for > >>the baggage of having to do the reflection work. Alas, that is the > >>price we pay for a strongly typed language. > >> > >>What I'm wondering is why more people don't use the declaration syntax > >>as a way to define methods in pages and use those methods to abstract > >>out some of the functionality they need? My answer would be that it is > >>generally frowned upon (by the MVC crowd) to put logic into the JSP page > >>and to a certain extent I agree. But, there are times where the logic > >>code is only used to modify the display and in those cases it seems to > >>me like putting that logic into a method within the JSP makes sense. > >> For example, when building the title string of the page you often have > >>to look up or build some sort of descriptive string from the various IDs > >>of the objects that are part of the request/session to the page. It > >>seems to me that doing this sort of operation is the kind of thing which > >>should be within the JSP page and using methods within the JSP page seem > >>to make even more sense as opposed to scriptlets. The alternatives are: > >>1) Put the "getPageTitle" method into the Model object. If the model is > >>supposed to capture the data of the object then it doesn't seem to me > >>like it should be cluttered with methods relevant to displaying > >>the object. > >>2) Put the "getPageTitle" method into the Controller object. Again, if > >>the controller is the driver of the business logic of the object(s) then > >>it too doesn't seem like the right place for methods relevant to > >>displaying the object. > >> > >>It seems like using methods in JSP pages is a good idea for certain > >>things. It also has it's downsides, the main one that I see is that > >>there is no inheritance among JSP pages. I wonder how hard this would > >>be to add? > >> > >>Does any one have any comments about why defining methods in JSP pages > >>is a good or bad idea? I would really appreciate hearing from you. > >> > >>Thanks for you time. > >>Alex. > >> > >> > >>*************** > >>Example method in a JSP page: > >>*************** > >> > >> > >> > >> > >><%@ page language="java" import="java.lang.reflect.*" %> > >><%! > >> public String getTitle(HttpServletRequest request) { > >> String id = request.getParameter("id"); > >> return "id: " + id; > >> } > >>%> > >><% Class c = this.getClass(); > >> > >> // The types for the method call > >> Class [] pTypes = new Class [1]; > >> Class hsr = > >>Class.forName("javax.servlet.http.HttpServletRequest"); > >> pTypes[0] = hsr; > >> > >> // Get the method > >> Method m = c.getMethod("getTitle", pTypes); > >> > >> // Build the list of parameters to the method > >> Object [] params = new Object [1]; > >> params[0] = request; > >> > >> // Invoke the method and get the result > >> String result = (String) m.invoke(this, params); > >>%> > >>Method Result: <%= result %> > >> > >> > >> > >> > >>-- > >>To unsubscribe, e-mail: > >> > >> > ><mailto:[EMAIL PROTECTED]> > >For additional commands, e-mail: > ><mailto:[EMAIL PROTECTED]> > > > > > > > >-- > >To unsubscribe, e-mail: > <mailto:[EMAIL PROTECTED]> > >For additional commands, e-mail: > <mailto:[EMAIL PROTECTED]> > > > > > > > > > > > -- > To unsubscribe, e-mail: > <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: > <mailto:[EMAIL PROTECTED]> > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
