Re: Opening ServerSocket in EJB

From:

Tom Anderson <twic@urchin.earth.li>

Newsgroups:

comp.lang.java.programmer

Date:

Tue, 31 Mar 2009 13:10:20 +0100

Message-ID:

<alpine.DEB.1.10.0903311304350.31295@urchin.earth.li>

On Mon, 30 Mar 2009, Arne Vajh?j wrote:

Tom Anderson wrote:

On Mon, 30 Mar 2009, mk wrote:

Is it possible (and sensible) to open ServerSocket in one of EJB? My web
application (realized in JEE) needs to establish TCP connection with
external application. Data exchange with this application is sometimes
initiated by the application and sometimes by web application on JEE
server.

I don't know if it will work - i believe the EJB spec bans the use of
Socket and ServerSocket from EJBs. However, there's a vague chance it will
work, and if it does, i imagine opening a server socket right from an EJB
will be the simplest way of solving your problem. However, it's naughty,
since in J2EE, managing sockets and so on is the app server's job. But ...

I would not be so worried about the management of sockets.

I would be more worried about the management of threads.

Threads being blocked while waiting for connection would
create a mess in thread management.

True. But you could set a timeout, and then do accepts in a polling way
from a managed thread. Your EJB's API could look like:

boolean checkForConnectionRequest(); // does ServerSocket.accept
DataObject processRequestFromClient(); // does Socket.read

etc. This would be a bit ugly, though.

tom

--
People don't want nice. People want London. -- Al