This patch adds support for pooling of ManagedConnections. A managed connection is responsible for managing a database connection in a transactional environment (typically called "Container Managed"). A managed connection opperates like any other connection when no gloabal transaction (a.k.a. XA transaction or JTA Transaction) is in progress. When a global transaction is active a single physical connection to the database is used by all ManagedConnections accessed in the scope of the transaction. Connection sharing means that all data access during a transaction has a consistent view of the database. When the global transaction is committed or rolled back the enlisted connections are committed or rolled back.
This patch supports full XADataSources and non-XA data sources using local transaction semantics. non-XA data sources commit and rollback as part of the transaction but are not recoverable in the case of an error because they do not implement the two-phase commit protocol.
The patch includes test cases and javadoc comments.