JBAS-4455 - LoadBalancePolicy that tries to pin all requests associated with a tx to one server

Couple of customers are interested in getting this feature included in the next EAP 4.2.0.GA CP
and I guess maybe in the next EAP 4.3.0.GA CP as well.

Please check the following wiki to understand the problems that this feature tries to resolve:
http://wiki.jboss.org/wiki/Wiki.jsp?page=TransactionStickyLoadBalancePolicies,

Please bear in mind that these are scenarios customers have encountered in the real world. I'll
add support case links in a minute.

Notes on potential risks or lack of them:

• This feature only applies to EJB2 beans. EJB3 requires further work due to missing features already existing for EJB2 beans.
• Unified/JRMP ha proxy classes have been modified which are key to good functioning of a remote call to an EJB2 bean. Relatively High Risk.
• Tracking of sticky nodes ha proxy classes is done via an already existing WeakHashMap, so don't foresee potential leaks associated with the addition of a new instance variable. Low Risk.
• New load balance policies have been created. If there were any problems with them, customers could revert on standard load balance policies. Low Risk.