Description:

WADI started life as a solution to the problems surrounding
the distribution of state in clustered web tiers, but is
becoming a more generalised distributed space service.
WADI's aim is to resolve many of the problems of dealing
with state in a cluster. This involves technologies such as :
WADI Core:
* Vertically - a distributed 'space' with pluggable/stackable
paging and persistance mechanisms (File, Database, etc.)
* Horizontally - A scalable, highly available, self-
partitioning, self-healing clustering substrate - a
distributed index/map
* Pessimistic locking semantics
* Transparent State->Invocation and Invocation->State migration
* Under construction - Various replication strategies
(including efficient in-vm replication) for HA state
WADI Web:
* A resolution to application vs container space concurrency
issues surrounding HttpSessions
* Pluggable HttpSession serialisation strategies -
per-session, per-attribute
* HttpRequest relocation (by redirection and proxying)
* Under construction - pluggable HttpSession replication
points - immediate, end-of-request-group, timed

WADI currently supports the following J2EE containers and
application servers:
* Tomcat 5.0.18+, 5.5.x
* Jetty 5.1.3+, 6.x
* OpenEJB (underway)
* Axis2 (underway)
* Geronimo-1.0.x/Tomcat or Jetty (underway)
* JBoss-4.x/Tomcat or Jetty