Application Logic : The first activity is login where the client gives his
UserID and Password. This request is validated and for a valid request the
other details ( i.e. customer no , account types and account no) were
fetched in the background. Now after this a new page is sent back to the
user with a menu with different options available to him. Selection of any
option (i.e. Balance checking, Amount Transfers) will generate a new
request by invoking a new servlet and this request will refer the same data
fetched earlier, through login process (i.e. customer no , account types
and account no) and process the request. It is required to maintain the
user specific data through out the session till the user terminates the
session.
Technical Approach : we are calling a specific servlet for a specific
client request with the required parameters and the servlet, which also
acts as a client for a session bean, will create a stateful session bean.
The parameter passed (i.e. UserId and Password) to this bean through the
servlet client will be used to get the detailed data from main database
where the necessary information is stored. We want all this information to
be alive till the user terminates the session.
We are considering two possible approaches for session / User Data
management on the EJB layer:
1. one stateful bean will maintain all the data throughout session.
In this approach we are having one centralized session bean which
holds the user/ session data and forwards the request to different Entity
beans after proper validations and with required request parameters. The
actual business operation will be done through the Entity Beans, which also
takes care of database specific jobs also.
Here, we need to maintain all the data alive in the stateful bean.
Every new request (i.e. every new servlet invoked form same client within
same session) needs to refer to specific instance of the bean (created
earlier with login process) for the additional data, which needs to be
added to the request and does the required process by invoking different
Entity beans where we are putting actual business code.
Kindly let me know if this approach is possible? If yes, then
a) Is it possible to keep the state of a stateful bean even if it's client
is not alive? If yes,
Then how do this and also how the instance of this stateful bean will be
made available to different requests ( new servlets)?
b) Can we use the Entity Beans for the purpose said above? If yes, then is
there any limitation on the instances, which can be created for Entity
beans within a container? how to design this so that the container can
hold the data/ entity beans instances for very large number of internet
users accessing the site ?
2. On a valid request we will create an entity bean, which will hold all
the data, fetched from the database for a specific user.
In this approach we have different Stateful beans with corresponding
servlet clients. Here the first process of login will invoke a stateful
bean specifically for login activity through a login servlet client. This
stateful bean will fetch the details from the main database. On a valid
request it will create an Entity bean containing all the user specific
data. We need to maintain userID or UserID& Password at the servlet level,
which will be passed with any request through servlet to new stateful
session bean, which will handle the client and bean state only. The user id
and password supplied with the request will be used as the primary key for
finding the Entity bean already created after login process.
Here the entity beans will be used for referencing user details only. The
interaction with the Main database is handled by different Session EJBs
depending upon their business logic.
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
