1. Java Channel Access Client and Server Library - status
Matej Šekoranja
Presented at the EPICS Meeting in Padova,

2. CAJ Client library Duplicate channel creations
Implementation of Channel Access in Java
100% pure Java solution, no JNI
Last release is: Release
People are happy, no problems….
Well… actually, there were 2:
Duplicate channel creations
Thanks to Marty and DLS for extensive testing
Slow connection speed when connecting to several thousands of channels at once
Thanks to Kay Kasemir and Tom Pelaia for testing
Solved in release (to be released in a week)
Cosylab 2008

3. Common CAJ (JCA) misuse
Major problem
flushIO(), pendIO(timeout), pendEvents(time)
pendIO(timeout) is being used for all
to be used only for sync. (blocking) get and channel creation
operations are context-wide, therefore must be used with care in multi-threaded applications
many threads calling pendIO(timeout)
simple brute-force synchronization will degrade performance
asynch. CA calls have to be used
non-perfect implementation of CA asynch. calls (get, put, create channel)
“basic” java synchronization mechanism, still in 99% code examples I’ve received not implemented in a right way
Cosylab 2008

4. CAJ Server library Already used by Gemini, DESY, Marty’s javaIOC
It’s a Java “equivalent” of C++ Portable Channel Access Server
Easy way to integrate non-EPICS data/variables into EPICS env.
clean, flexible, programmer friendly design
easy != something that is possible
easy == couple of minutes
Complete, finished implementation
Release plan: this year.
Cosylab 2008

5. Future work
None? 
A few problem reports from the first release (Nov 2004), none for a half of a year (extensive users are happy with v1.1.5)
Extensions to CA (structures)? EPICS v4?
CAJ server/client is based on state-of-the-art communication ”framework”
Acceptor/connector: an object creational pattern for connecting and initializing communication Services
Leader/Followers: design pattern for efficient multi-threaded event demultiplexing and dispatching
Reactor: synchronous I/O
 can be used as a base to develop new communication protocols
Cosylab 2008

6. Thank You for Your Attention
Cosylab 2008