Re: Socket factories with JERI

Martin Cornelius wrote:
> Hi there,
> 
> i want to get a bit more control over read and write timeouts encountered in remote 
> calls on objects objects exported via JERI. I learned so far, that this should be possible 
> by creating my own Socket Factories and passing them to 
> net.jini.jeri.tcp.TcpServerEndpoint.getInstance()

Hi Martin,

For the connect timeout you can also use constraints, see the class
level documentation net.jini.core.constraint.ConnectionRelativeTime. If
you pass these in as part of the server constraints they will be
'enforced' by the Jini ERI proxy. As advise do it as a preference, that
way the client is able to override it with a required connect timeout
constraint.

There is no equivalent for the read timeout for remote method
invocations. IIRC the reason for not having a read timeout is due to the
fact that in Jini ERI a socket connection can be reused for multiple
invocations and the multiplexing protocol so that you can't have a 1:1
relation between the method constraints and the socket connection. But
no doubt there are people who are in a far better position to explain
the whys. There is a read time constraint though for unicast discovery,
see com.sun.jini.discovery.UnicastSocketTimeout. Also it is rather
tricky to have a read timeout, as it would place sort of an upper bound
for the time a computation may take at the server side.

Not that it shouldn't be handy to have a constraint to indicate the
maximum time one is willing to spend waiting for a response, although a
read timeout is not the proper mechanism for that, and I believe some
people haven't made up their mind about whether such a constraint would
be a good thing IIRC.

But as you said it is possible to pass in a socket factory as part of
the call to TcpServerEndpoint.getInstance, don't forget to make the
socket factory class serializable and part of your download JAR file.
And if secure communication is required you need to write a trust
verifier for that socket factory and a bootstrap mechanism to get that
trust verifier in a trusted way over the wire, so I hope the connect
constraint will suit you.

Personally I find the socket connect timeout rather essential, the read
timeout scares me for remote method invocations.
-- 
Mark

--------------------------------------------------------------------------
Getting Started:     http://www.jini.org/wiki/Category:Getting_Started
Community Web Site:  http://jini.org
jini-users Archive:  http://archives.java.sun.com/archives/jini-users.html
Unsubscribing:       email "signoff JINI-USERS"  to [email protected]