Re: Stateful Web Services...

Thank you all for your answers, but i still have doubts about the Web Services and the way they are used, especially their life cycle inside the Web Servers (Tomcat, JBoss etc).

Related to the Stateless vs Statefull web services i agree that we can have both and in the architecture there is nothing that says the Web Services are Stateless, although the information that we can find in the Internet always present web services as being stateless and if you want to make them stateful you need to take some specific actions. 

About Choreography and orchestration initiatives like WS-CDL and BPEL4WS, they allow us to define statefull interactions and cooperation between diferent Web Services by defining the messages exchanged betwenn the diferent participating Web Services.

Although there is one last thing that is confusing me. A Web Service life is controled by a Web Server like for example Tomcat. When a request arrives, the class that implements the request is dynamically loaded and the request is executed. When the request ends the class is deallocated. This means this class cannot maintain its internal state. Any kind of data that was kept by it is garbage collected. 

One of my questions is: 

Is it possible now to design a Web Service that is automatically allocated when the user makes a request, and is only deallocated/stops running when i want? This means that it will run while the Web Server (Tomcat) is running.

Another thing is, the Web Server for multiple requests allocates multiple classes, What if i want to have my class to take care of the different connections? is this possible?

I think this questions are more related to the way the Web Services are handled by the Web Servers like Tomcat, anyway i cannot find any information about this in the Internet and i have to make an architectural decision about the technology to use in a project i am involved. Our architecture is higly distributed and we will need to have callback mechanisms, Notifcation, etc. We will need to deal yourselfs with multi-sessions by using multithreading etc etc, and the way i see things is that Web Services is not so good candidate has for example CORBA.

Please advise me on this,


Regards,

Cristóvão André Carvalho Bento
Software Engineer

Critical Software SA
Parque Industrial de Taveiro, Lote 48
3045-504 Coimbra, Portugal
Tel:+351.239 989 108 Fax:+351.239 989 119
http://www.criticalsoftware.com
mailto:cbento@criticalsoftware.com


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