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From Simon Aquilina <>
Subject RE: J2EE Connector 1.5 Specification
Date Thu, 25 Sep 2008 09:46:57 GMT

Hi David,

Thanks again for the reply. All your comments are very useful for me since I get a better
picture and have an idea of what alternatives I can use :)

As you can imagine jaxws immediately took my attention. I agree with you that this is large
subject to try to describe in an email and found this good tutorial here to understand this
subject better (

However I do have a simple question; I had already considered using web services for my design.
For Tomcat I was considering using Axis. However I still had the problem that the services
would be available over the http protocol and the http protocol connector is only inbound.
I think (although not sure) that this would be the same scenario with Geronimo. If so then
I would still need to develop my own connector that can handle inbound and outbound messages.

For me having an EIS that is able to establish a connection and send messages to a remote
client is the most important aspect of all this.

Simon J.

Subject: Re: J2EE Connector 1.5 Specification
Date: Thu, 25 Sep 2008 01:24:41 -0700

On Sep 25, 2008, at 1:03 AM, Simon Aquilina wrote:Hi David,

Thanks for your reply. I started reading the J2EE Connector 1.5 Specification yesterday and
hope this will help me to better understand how J2EE connectors work and thus use the maximum
out of them :)

To say the truth I am interested in building a connector which is able to receive inbound
and send outbound messages; in other words a remote client would be able to establish a connection
and send messages to an EIS deployed on the application server and the EIS would (also) be
able to establish a connection and send messages to the remote client. When I started developing
my connector for Tomcat I was trying to achieve this. Due to my (lack) of experiance I thought
this was not part of the J2EE connector specification; now that I read the documentation it
seems it is. 

My main aim is to find an application server which I can use as the base for any network solution
I want to develop (not only web applications). 

When I developed small network applications I realised that most of the time all my client/server
application work exactly in the same way and very similar to how a web/application server
works. However, since I mostly developed web applications, I thought that web/application
servers could only handle inbound messages (this was before I read the first chapters of the
J2EE connector specification). For this reason I tried to develop a protocol handler on Tomcat
that was able to estable a connection with a remote client and thus make it able to handle
inbound and outbound messages. Then after hitting a brick wall with Tomcat I did some more
research and found Geronimo. I want to continue on Geronimo now; also because it is highly
modularised which I like. 

The sceanrio I have in mind is as follows:

Client (A) --[send message]--> EIS --[send messages]--> Client (B) --[send confirm message]-->
EIS --[send confirm message]--> Client A

This means that asynchronus communication would be a very intresting concept :) 
I think either jms or remote ejbs will do what you want with no infrastructure/middleware
coding on your part.
I'm not entirely sure you are using "asynchronous" in its usual meaning.  With (asynchronous)
jms you'd have a thread in client A that would send a message.  As soon as it is sent the
thread will get control again (before the message is delivered) and can continue with other
work.  The message could be received by an MDB B which would process it and possibly send
one or more messages in response, to any destination.  A could have another thread listening
for responses on this destination, or the original thread could listen (and block) waiting
for a resonse.
If (as your diagram indicates) you want A to receive a response before continuing with other
work, I think EJBs alone will do what you want.  A would look up in jndi an ejb business interface
and would call appropriate methods on it.  The ejb (B) would process the message (method call
arguments) and return the response.  If A is not a java client you can use CORBA to communicate
with a (java) ejb, although this is not the easiest thing to get working ever invented.
Another option if you need looser coupling is jaxws web services which among other things
can provide access to ejbs, where the request and response messages are xml documents.  This
is a rather large subject to try to describe in an email however.
In my experience j2ca outbound connectors are mostly useful when you need to communicate with
a system you have little control over such as an existing database or messaging system.  If
you are writing both the client and server there is almost always a more convenient, flexible,
and easier solution. 
Hope this is helpfuldavid jencks

I do not have a dead line for this; for me the most important thing is to learn. So feel free
to suggest any reading. I am also happy to read example code since I feel this helps me better
to understand how things work :)

Thanks again,
Simon J.

Subject: Re: J2EE Connector 1.5 Specification
Date: Wed, 24 Sep 2008 09:09:33 -0700

On Sep 24, 2008, at 5:36 AM, Simon Aquilina wrote:Hi Juergen,

Thanks for your quick reply. That is very similar to what I want to try and achieve and the
concept is very similar to the one I was trying to achieve on Tomcat! Is there something like
this provided by the Apache Software Foundation? 
Based on the level of writing in the documentation I would be careful using txconnect. I only
looked at the documentation for a couple minutes.  While I did not see any of the glaring
errors I usually find in j2ca projects it looks to me as if there were quite a few misleading
If you are looking for a framework for building outbound j2ca connectors, there is also the
codehaus tranql project which is under asl 2.0.  Geronimo ships with the tranql db adapters
to provide jdbc connectivity.
However, based on your original attempt to do something related to a tomcat http connector
I really doubt you are interested in an outbound connector, which is designed to let your
server program connect to other programs such as a database, SAP, CICS, etc as a client.
You might possibly be interested in a j2ca inbound connector.  The standard example of these
is a jms implementation supplying messages to mdbs.
Perhaps you could explain what you are trying to do:
- what the source of messages is- what transport and protocol they travel over- what the consumer
of the messages is- whether the communication is synchronous (message receiver sends a reply
back to the message sender) or asynchronous (no reply to messages, such as with MOM or jms)-
which role(s) your server program will be playing- how many clients, servers, and messages
you want to handle
thanksdavid jencks

Simon J. 

> Date: Wed, 24 Sep 2008 14:04:34 +0200
> From:
> To:
> Subject: Re: J2EE Connector 1.5 Specification
> Have a look at
> it might make your job a lot easier.
> On Wed, Sep 24, 2008 at 1:30 PM, Simon Aquilina <> wrote:
> > Hi,
> >
> > I am interested in developing a custom connector for Geronimo so that the
> > latter can communicate using a protocol different then Http. I had started a
> > similar project on Tomcat, however I then realised that Tomcat treats all
> > requests as Http requests internally.
> >
> > I therefore decided to focus my energy on Geronimo since this is a real
> > application server and J2EE certified.
> >
> > I thought that first of all I should read the J2EE Connector 1.5
> > Specification. Is this the right place to start? Or Geronimo has some other
> > documentation which I should consider? I have tried the Documentation
> > section to see what is available but (like in the case of Tomcat) I did not
> > find much related to connectors.
> >
> > Also please do correct me if I say anything stupid. I am not an expert
> > programmer nor do I know how Geronimo works inside out. However I am willing
> > to do an effort and learn and am willing to put as much time as needed to
> > learn things correctly.
> >
> > Thanks and Regards,
> > Simon J.
> >
> > ________________________________
> > Explore the seven wonders of the world Learn more!

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