Hi,
See inline
-----Original Message-----
From: Nitin Goyal [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 18, 2001 3:54 PM
To: [EMAIL PROTECTED]
Subject: Re: Newbie Question
Hi,
An EJBObject is network enabled and callable from other JVMs as it
implements the Remote interface (javax.ejb.EJBObject extends
java.rmi.Remote).
> file://Yes for promoting location trasparency, the JNDI lookup is used to
get the
> ref to the EJBHome. Instead of looking for EJBHome, lookup can be done for
> EJBObject.
How does a client acquire a reference to the EJBObject if they are residing
on separate machines?
//Even EJBHome object resides in the different machine.
How will a client find existing EJBObjects?
//A client can find the existing object using EJBObject only. It will ask
the EJBObject for another object and if it exists it will return the ref to
the object similar to what EJBHome is doing.
How will the EJBObjects will be created and removed?
//Object will be created when the lookup is done and will be removed like
wise.
Home Interfaces simply define the methods for creating/destroying/finding
EJBObjects. The containter's home object IMPLEMENTS your home interface.
//I never said that home object does not implement the home interface why
can't EJBObject implement the home interface also providing features for
removing and finding other EJB objects.
Thus the steps are:
1. Client request for a new EJBObject.
2. The HomeObject, which implements the Home Interface, intercepts this call
and creates an EJBObject.
3. The HomeObject returns the EJBObject ref to the client.
//These steps are valid for your way of viewing the things.
Still out in the cold? :-)
//Yes
Regards,
Nitin
----- Original Message -----
From: "Ripan Bansal" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, January 18, 2001 2:36 PM
Subject: Re: Newbie Question
> My doubts are inline
>
> -----Original Message-----
> From: Nitin Goyal [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, January 18, 2001 1:59 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Newbie Question
>
>
> Hi,
>
> EJBObjects:
> The client does not invoke a method directly on the actual bean instance.
> Instead, the call is intercepted by the container and =
> delegated to the bean instance. Reasons:
>
> 1. The EJB is not network enabled and the container handles the networking
> for it (by wrapping the bean in a network enabled object).
> 2. The Container can implement Security, Pooling, Transaction Management
> logic to the request.
> 3. The Container can track all the methods that were called on the bean,
> load balance etc.
>
> The EJBObject is a (surrogate) object that knows about management,
security
> etc. It performs the logic that the container requires before a method is
> serviced by a bean class instance. All EJBObjects have container specific
> code inside them.
>
> file://Ripan
> file://This part is okay.
>
> EJBHome:
>
> The client cannot invoke an EJBObject directly as they are on separate
> machines.
> file://I am not clear about this thing. Is there always something in
between the
> EJBObject and the client. As fas as i know EJBObject is network enabled.
It
> is directly accessed from the client machine.(Ofcourse with hidden stub
and
> skeleton)
>
> Alos the EJB Specification espouses location transparency - =
> the client should not be aware where the EJBObject exists.
> To acquire an EJBObject, the client requests the EJBObjectFactory for an
> EJBObject. This factory - which is responsible for creating and =
> destroying EJBObjects, is called Home Object.
>
> file://Yes for promoting location trasparency, the JNDI lookup is used to
get the
> ref to the EJBHome. Instead of looking for EJBHome, lookup can be done for
> EJBObject.
> I am still not clear about the need of the EJBHome.
>
> Guess this will shed some light.
>
> Nitin
>
> ----- Original Message -----
> From: "Ripan Bansal" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, January 18, 2001 12:18 PM
> Subject: Newbie Question
>
>
> > I am new to all this stuff. I have just started learning EJB due to my
> > project requirements. I have a very basic question regarding the
design
> of
> > the EJB architecture. I want to know why do we need to have EJBHome and
> > EJBObjects? Why can't we do away with just one object implemented by the
> > proprietry Application server.
> >
> > Suggest me some good material to start with. Any pointers in this regard
> are
> > highly appreciated.
> > Thanks
> > Ripan
> >
> >
>
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> >
> >
>
>
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