Resource Handling Mechanism 

Application components that access a database, such as entity enterprise beans, need transactions to ensure the integrity of the data stored in the database. Furthermore, certain resources, such as connections, are used to enable the execution of the distributed transactions. The process of assigning a resource to a transaction is called enlisting. The process of releasing resources is called delisting.

The resource handling mechanism is the component that manages the use of resources in the transactions. It registers the used resources and takes care of their release. The functions of this component are provided by the Transaction Service and the Connector Container Service.

In the SAP J2EE Engine you can connect to back-end systems using J2EE Connector Architecture resource adapters. The Connector Container Service is a container for these adapters and provides their access to system-level resources. It is responsible for the centralized management of the connections provided by the deployed adapters in terms of transactions, security and connection pooling. The behaviour of the connections that you obtain and use in your applications depends on the following factors:

·        If the connection is used in a transaction;

·        If it is a shared resource.

The SAP J2EE Engine also provides the JDBC Connector Service that implements the logic of a resource adapter for connections to a relational database. You can use this service to register DataSources, which act as factories for database connections. For more information about what is specific in the management of these connections, see Database Connection Management.