Relational resource adapters and JCA
A resource adapter is a system-level software driver that a Java™ application uses to connect to an enterprise information system (EIS). A resource adapter plugs into an application server and provides connectivity between the EIS, the application server, and the enterprise application.
WebSphere® Application Server supports JCA versions 1.0, 1.5 and 1.6, including additional configurable features for JCA 1.5 resource adapters with activation specifications that handle inbound requests. The JCA Version 1.6 specification also adds support for Java annotations in RAR modules. For more information on annotation support see the topic, JCA 1.6 support for annotations in RAR modules.
Data access for container-managed persistence (CMP) beans is indirectly managed by the WebSphere Persistence Manager. The JCA specification supports persistence manager delegation of the data access to the JCA resource adapter without knowing the specific backend store. For the relational database access, the persistence manager uses the relational resource adapter to access the data from the database.
You can find the supported database platforms for the JDBC API at the WebSphere Application Server prerequisite website.
Java EE Connector Architecture and WebSphere relational resource adapters
An application server vendor extends its system once to support the Java Platform, Enteprise Edition Connector Architecture (JCA) and is then assured of seamless connectivity to multiple EISs. Likewise, an EIS vendor provides one standard resource adapter with the capability to plug into any application server that supports the connector architecture.
The product supports any resource adapter that implements version 1.0, 1.5 and 1.6 of this specification. IBM® includes WebSphere MQ and the Service Integration Bus with the Application Server, and IBM supplies resource adapters for many enterprise systems separately from the WebSphere Application Server package, which include but are not limited to, the Customer Information Control System (CICS®), Host On-Demand (HOD), Information Management System (IMS), and Systems, Applications, and Products (SAP) R/3 .
The general approach to writing an application that uses a JCA resource adapter is to develop EJB session beans or services with tools such as Rational® Application Developer. The session bean uses the javax.resource.cci interfaces to communicate with an enterprise information system through the resource adapter.
WebSphere Relational Resource Adapter
WebSphere Application Server provides the WebSphere Relational Resource Adapter implementation. This resource adapter provides data access through JDBC calls to access the database dynamically. The connection management is based on the JCA connection management architecture and provides connection pooling, transaction, and security support. The WebSphere RRA is installed and runs as part of WebSphere Application Server, and needs no further administration.
The RRA supports both the configuration and use of JDBC data sources and JCA connection factories. The RRA supports the configuration and use of data sources implemented as either JDBC data sources or Java EE Connector Architecture connection factories. Data sources can be used directly by applications, or they can be configured for use by container-managed persistence (CMP) entity beans.
- For information about resource adapters and data access, see the topic Data access portability features.
- For RRA settings, see the topic WebSphere relational resource adapter settings.
- For information about enterprise beans, see the topic EJB applications.