The Connector architecture defines system-level contracts between an application server and an EIS that enable outbound connectivity to an EIS: connection management, transaction management, and security.
The connection management contract supports connection pooling, a technique that enhances application performance and scalability. Connection pooling is transparent to the application, which simply obtains a connection to the EIS.
The transaction management contract between the transaction manager and an EIS supports transactional access to EIS resource managers. This contract lets an application server use a transaction manager to manage transactions across multiple resource managers. This contract also supports transactions that are managed inside an EIS resource manager without the necessity of involving an external transaction manager. Because of the transaction management contract, a call to the EIS may be enclosed in an XA transaction (a transaction type defined by the distributed transaction processing specification created by The Open Group). XA transactions are global: they can contain calls to multiple EISs, databases, and enterprise bean business methods. Although often appropriate, XA transactions are not mandatory. Instead, an application can use local transactions, which are managed by the individual EIS, or it can use no transactions at all.