J2EE Connectors

The J2EE Java Connector Architecture (JCA) provides a standard architecture for connecting J2EE Application Servers to enterprise information systems (EISs). An enterprise information system is any product that manages the information infrastructure of an enterprise. Examples of an EIS include Enterprise Resource Planning systems, mainframe Transaction Processing Monitors, and legacy databases.

The JCA defines a standard framework in which resource adapters can be developed for specific EIS products. A resource adapter plugs into an application server, offering all of the functionality needed to connect to and interact with the EIS. This integration extends to connection management, security, and transactions, providing a rich and robust way of interfacing with these external systems. J2EE components running on the application server then can interact with the resource adapter in a standard manner, and the resource adaptor in turn will interact with the EIS. Because the JCA is a requisite part of the J2EE platform, the EIS vendor can provide a single resource adapter that allows any J2EE application server to connect to the EIS.

The JCA framework deals with three important components:

System-level contracts

The system-level contracts, implemented in WebLogic, define the interface between the application server and the resource adapter. This system-level interface deals with managing a pool of connections to the EIS, enabling the EIS resource manager to participate in local or distributed transactions, and providing secure access to EIS resources.

Common Client Interface (CCI)

The CCI provides a generic interface to the resource adapter, allowing you to develop applications that work across heterogeneous EISs. J2EE components can use the CCI to interface with either the resource adapter or an EIS-specific interface. The resource adapter vendor is not required to implement the CCI.

Packaging and deployment

The JCA defines a standard way of packaging resource adapters and deploying them as part of an enterprise application.

In this chapter, we'll examine how WebLogic manages a pool of connections to the EIS and the various transaction levels and sign-on mechanisms supported by WebLogic. We'll cover how WebLogic lets you map credentials of a WebLogic user to valid user credentials on the EIS. We'll also look at the various deploy-time and runtime configuration settings that apply to any J2EE connector. Along the way, we'll cover how to configure and use a J2EE-compliant resource adapter.

The terms resource adapter and J2EE connector will be used interchangeably.