Servers in a network cluster can each store a copy of a data item in local
cache, providing read access to these copies through read-only entity beans. The
original data item in the database can be updated through a read/write entity bean
one of the cluster servers. That cluster server has access to an invalidation target,
which contains identification information relating to copies of the data item stored
on servers in the cluster. Once the read/write bean updates the data item in the
database, an invalidate request can be sent or multicast to all cluster members,
or to any read-only bean or server contained in the invalidation target. Each server
or read-only bean receiving the request knows to drop any copy of the data item
in local cache, and can request a current copy of the data item from the database.
