Loading dynamic Content

Question

I'm developing a site for an Intranet. Depending on the logged user I want to show him the menues he has access to.
To do that I thought of writing a jsp page that shows the menu and include it in a main page. But how does the bean used in this jsp page know who logged in he previous page?
The solution I found is to save the user in a session, and add two methods in the bean that loads the menu to set a get the user. Is this a good solution?
The code of the jsp page that loads the menu is:
<jsp:useBean id="modulosId" class="beans.configMenu.BeanAdmModulos" />
<table width="40%" border="0">
<% String nombreUsr=(String)session.getAttribute("sesion.usuario");%>
<% modulosId.setUsuario(nombreUsr); %>
<% java.util.Vector modulos = modulosId.getModulos(); %>
<% for(int i = 0; i < modulos.size(); i++) { %>
<tr>
<%= modulos.elementAt(i)%>
</tr>
<%}%>
</table>
Related with this I have another question. The menues I will load will be in a database. Each time I load the menues I will have to query the database. Is it better to add to the session all the menues or querying the database each time I load the page wouldn't bring performance penalties?
Thanks for your comments

Answer 1

I'm developing a site for an Intranet. Depending on
the logged user I want to show him the menues he has
access to.
To do that I thought of writing a jsp page that shows
the menu and include it in a main page. But how does
the bean used in this jsp page know who logged in he
previous page?
The solution I found is to save the user in a
session, and add two methods in the bean that loads
the menu to set a get the user. Is this a good
solution?
User credentials are often cached in the session, so this is fine. Your main decision will be whether to check the user's authorization (privileges, roles, rights, etc.) with each request or to cache those results with the user's authentication (logon) credentials in the session as well.
The code of the jsp page that loads the menu is:
<jsp:useBean id="modulosId"
class="beans.configMenu.BeanAdmModulos" />You have the option here of declaring this bean's scope to be 'session'. Otherwise, this is fine if you are manually checking the session itself (as you are doing below).
<table width="40%" border="0">
<% String
ng
nombreUsr=(String)session.getAttribute("sesion.usuario
");%>
<% modulosId.setUsuario(nombreUsr); %>
<% java.util.Vector modulos =
= modulosId.getModulos(); %>
<% for(int i = 0; i < modulos.size(); i++) { %>
<tr>
<%= modulos.elementAt(i)%>
</tr>
<%}%>
</table>
Related with this I have another question. The menues
I will load will be in a database. Each time I load
the menues I will have to query the database. Is it
better to add to the session all the menues or
querying the database each time I load the page
wouldn't bring performance penalties?
It is a speed versus memory tradeoff. If you are going to cache the menus, I would suggest caching the mapping between a role and a menu (or whatever equivalent exists in your app). There should be fewer roles than users; hence, this should use less memory. The solution may need some tweaking if users can have multiple roles.
Thanks for your commentsYou're welcome.
- Saish