user manual

Chapter 26: VisiConnect overview 285
Resource Adapters
You specify a reference to the RAR Java classes by adding a ClassPath=
entry in the RAR Manifest.mf file. You can also store the EJB Java classes in
the same JAR file that is contained within the EAR. This scenario provides a
"support" JAR file that contains Java classes for the components in the EAR
that require them.
Secure Password Credential Storage
VisiConnect provides a standard method for Resource Adapter deployers to
plug in their specified authorization/authentication mechanism through secure
password credential storage.
This storage mechanism is used to map user roles (Borland Enterprise Server
roles, which may be associated with Borland Enterprise Server username and
password combinations or credentials) to resource roles (EIS roles, which
may be associated with EIS user name and password combinations or
credentials).
Connection Leak Detection
VisiConnect provides two mechanisms for preventing connection leaks:
■
Leveraging a garbage collector
■
Providing an idle timer for tracking the usage of connection objects
Security Policy Processing of ra.xml Specifications
VisiConnect provides a set of security permissions for execution of a
Resource Adapter in a managed runtime environment. Borland Enterprise
Server also grants a Resource Adapter explicit permissions to access system
resources.
Resource Adapters
Source code for six Resource Adapters are provided with VisiConnect as
examples. These Resource Adapters are wrappers for JDBC 2.0 calls. The
Local, Remote and Secured JDBC Connectors expose these calls directly via
the JDBC 2.0 API. The Local, Remote and Secured CCI Connectors, exposes
these calls indirectly via CCI. Deployment descriptors supporting the three
transaction levels are provided for each Resource Adapter.
Simplified application examples for the three JDBC Resource Adapters are
provided with VisiConnect. An EJB is used to model the data in the EIS, and a
J2EE client and a Servlet are used to query the Resource Adapter and display
the output. The example uses any RDBMS which is supported by a JDBC 2.0
compliant driver. By default, the examples are configured to use JDataStore
as the EIS, but it is a straightforward task to configure them to use any JDBC
2.0 RDBMS. The components are packaged as a J2EE Application. For more
information, refer to the VisiConnect example README provided with the
Borland Enterprise Server.