== Connector Architecture ==

The Connector architecture enables Java EE components to interact with enterprise information systems (EISs) and EISs to interact with Java EE components. EIS software includes various types of systems: enterprise resource planning (ERP), mainframe transaction processing, and nonrelational databases, among others. Connector architecture simplifies the integration of diverse EISs. Each EIS requires only one implementation of the Connector architecture. Because an implementation adheres to the Connector specification, it is portable across all compliant Java EE servers.

 {{attachment:connector-accessingEIS.gif}}

Stored in a ''Resource Adapter Archive'' (RAR) file, a resource adapter can be deployed on any Java EE server, much like the EAR file of a Java EE application. An RAR file may be contained in an EAR file, or it may exist as a separate file. See Figure 35-2 for the structure of a resource adapter module.

A resource adapter is analogous to a JDBC driver. Both provide a standard API through which an application can access a resource that is outside the Java EE server. For a resource adapter, the outside resource is an EIS; for a JDBC driver, it is a DBMS. Resource adapters and JDBC drivers are rarely created by application developers. In most cases, both types of software are built by vendors that sell products such as tools, servers, or integration software.
