Re: Managed Bean OO Design question

Duong BaTien Thu, 07 Apr 2005 07:22:29 -0700

Hello:

Have you looked at Struts-shale that give you DialogBean (session scope) which control the flow of different pages and ViewController (request scope) which can pull data from other beans and control the current page request?

I found DialogBean very useful even in the case you do not need to control the page flow. Shale has facilities to further extend Jsf and enable finer control.

BaTien
DBGROUPS

Heath Borders wrote:

Here's the way we've done it:
Our app is mainly for data collection. Usually, its just a big master-detail wizard, but sometimes its more complicated.

Let's start with a simple example. I have an application that lets users input organization information. The users start by selecting an Organization from a <h:selectOneListbox />. Then, they proceed to a page where they can enter a description and tax id for the Organization. Next, they go to an address editor, where they can add multiple addresses. Then, they go to a phone editor, where they can editor multiple phones. Finally, they go to a page where they can choose Organization types from an <h:selectManyCheckbox />.

The way I chose to approach this problem is to have one master application bean and multiple sub-application beans. The master application bean contains all the common information for all the pages of the app. In this case, its just the Organization the user selected from the list. The master bean also contains all the sub-application beans, one for each page. So, there is an OrgSearch bean for the first page, an OrgGeneral bean for the second page, an OrgAddresses bean for the third page, an OrgPhones bean for the 4th page, and an OrgTypes bean for the 5th page.

The subapplication beans are setup so that they are constructed when the master bean is constructed, and are passed a reference to that master bean. That way, they can access common information. This setup provides good separation, and also good sharing.

On Apr 6, 2005 8:41 PM, *Ray Clark* <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote:
    I've been on this list for awhile now and I don't
    remember a discussion about how to architect managed
    beans for a page.  (Please bear with me as this has
    turned into a rather long post.)  I see 2 alternatives
    with how to set up the classes for my managed beans.
    First, for sake of discussion, here is my problem set.
    On my page I have 2 selectOneMenu lists and 1
    dataTable.  The first selectOneMenu is a list of
    subjects, the second is a list of teachers, and the
    dataTable is a list of classes.  Selecting the subject
    and teacher determines which classes will be displayed
    in the list of classes.  The list of classes is
    displayed when the search commandButton is clicked.
    Now, the question is, do I have just 1 managed bean
    for the page?  That bean would have as a class
    variables, a teachers list, a selected teacher String,
    a subjects list, a selected subject String, and a
    classes list.  Then for methods it would have all of
    the getters and setters for these fields in addition
    to the method for the commandButton.  The method for
    the commandButton would call the business layer to
    actually retrieve the list of classes from the data
    layer.  The getter for the teacher list would call the
    business layer to actually retrieve the list of
    teachers, etc.
    I could have another page in my app (or another app),
    that needs an inputText field for a teacher, and
    possibly a method to validate the name entered to see
    if it was valid.
    So with this design managing of teacher information
    would be spread across multiple beans.
    Or, do I have 1 managed bean per object.  So I would
    have a managed bean to manage teacher information, a
    managed bean to manage subject information, and a
    managed bean to manage class information.
    This would group all of the presentation for an object
    into 1 class, but it causes complexity when one class
    needs access to the information in another class in
    order to retrieve its data.  It also seems to make the
    managed bean organized more like the data layer than
    the presentation layer.
    In either case, the managed bean would just be for
    passing the data to the JSF page and for calling the
    business layer to retrieve, maintain, etc, the data.
    I like aspects of both designs.
    Maybe there is another better solution.  I have just
    been learning the tags and haven't given much thought
    to the design of the beans yet.  But it's time for me
    to start thinking about how to set up my managed
    beans, hence I am asking for your advice.
    From an OO perspective, which way do you experienced
    JSF programmers have things set up?
    Thanks,
    Ray
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