Re: Mapping SQL Result Sets to Browsers -- WEB400

Nathan-

Would it be too much to assume that the List could be referenced directly
from JSPs and more specifically from JSF tags? Would the List be suitable for
consumption by the "presentation layer"?

Your assumptions are correct.
The DAO class I wrote could be directly consumed by the presentation
layer or from a business layer, or both.

In Java code you would use the DAO as follows:

RegistrationDaoImpl regDAO = new RegistrationDaoImpl();

List myList = regDAO.retrieveRegistrations();

// If list is not empty, print it out.
for(int i =0; i< myList.size(); i++){
Map current = myList.get(i);
System.out.println("First Name: " + current.get("FIRST_NAME") );
System.out.println("Last Name: " + current.get("LAST_NAME") );

}

JSP taglibs, JSF, Struts and other presentation frameworks can easily
deal with maps and lists. Notice there is no mention of Spring APIs or
JDBC APIs outside the dao implemetation class. So I could easily
switch to another mechanism without touching business logic or
presentation logic. Or I could use a different mechanism ( such as
LDAP) in different DAO implemtations.

On a side note, there are optional integrations between Spring IoC and
many presentation frameworks. So when I use Spring IoC I can eliminate
the line of code that calls the DAO constructor. ( RegistrationDaoImpl
regDAO = new RegistrationDaoImpl(); )

-Sarah

-Sarah

On Mon, Jul 7, 2008 at 6:43 PM, Nathan Andelin <nandelin@xxxxxxxxx> wrote:

Thanks, Sarah. Your example of a retrieveRegistrations() method offers a good illustration of building a collection of rows and columns from an SQL result set. Would it be too much to assume that the List could be referenced directly from JSPs and more specifically from JSF tags? Would the List be suitable for consumption by the "presentation layer"? At this point you've only characterized it as a Data Access Object.

Nathan.

----- Original Message ----
From: Sarah Poger Gladstone <listmember@xxxxxxxxxxxxxx>
To: Web Enabling the AS400 / iSeries <web400@xxxxxxxxxxxx>
Sent: Monday, July 7, 2008 4:19:35 PM
Subject: Re: [WEB400] Mapping SQL Result Sets to Browsers

Nathan - Below I have pasted a method for my DAO example that shows an
example of a multi-row, multi-column result from a query:

public List retrieveRegistrations(){
List reg_list = null;
reg_list = getSimpleJdbcTemplate().queryForList( "Select * from PERSON" );
return reg_list;
}

If there are 3 records each with 2 columns, then the list returned
will look like:

List{
0 - Map {FIRST_NAME= "Sarah", LAST_NAME="Gladstone"}
1 - Map {FIRST_NAME= "Simone", LAST_NAME="Gladstone"}
2 - Map {FIRST_NAME= "John", LAST_NAME="Doe"}

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