Data access application programming interface support
Applications can access the backend data through the standard J2EE 1.3
defined application programming interfaces (APIs).
The standard APIs do not always provide a complete solution for an application
that runs in an application server. For example, the JDBC programming model
sometimes does not completely work with the J2EE Connector Architecture (JCA)
Specification (even though the JCA architecture has explicitly specified that
it integrates with the JDBC programming model). These gaps cause some incompatibility
between the JDBC and JCA programming models.
When getting and using shareable connections in a global transaction, it
is not valid to change a property on the connection after you obtain it. Changes
can unknowingly affect other users who share the same connection.
The J2EE Connector Architecture (JCA) Specification supports telling the
resource adapter the specific properties settings at the time you request
the connection (using the getConnection method) by passing in a ConnectionSpec.
The ConnectionSpec contains the necessary connection properties used to get
a connection. After you obtain a connection from this environment, your application
does not need to alter the properties.
The JDBC programming model does not have the same interface to specify
the connection properties. Instead, it gets the connection first, then sets
the properties on the connection. In the case of a shareable connection, changing
the connection properties impacts all the connections shared with the same
physical connection.
WebSphere Application Server provides the following extensions to fill
in the gaps between these two specifications.
- WSDataSource interface - this interface extends javax.sql.DataSource,
and enables a component or an application to specify the connection properties
through the WebSphere Application Server JDBCConnectionSpec to get
a specific connection.
- getConnection(JDBCConnectionSpec) - this method returns a specific
connection which has the JCA compliant connection behavior.
- For more information see the Javadoc wsdatasource in the Javadoc
index.
- JDBCConnectionSpec interface - this interface extends the com.ibm.websphere.rsadapter.WSConnectionSpec,
which extends javax.resources.cci.ConnectionSpec. The standard ConnectionSpec interface
provides only the interface marker without any get and set methods. The WSConnectionSpec and JDBCConnectionSpec define
a set of get and set methods used by the WebSphere Application Server run
time. This interface enables the application to specify all the essential
connection properties in order to get an appropriate connection. You can create
this class from the WebSphere WSRRAFactory. For more information see the
Javadoc JDBCConnection in the Javadoc index.
- WSRRAFactory - this is the Relational Resource Adapter Factory
which allows the user to create a JDBCConnectionSpec or other resource
adapter related object. For more information see the Javadoc wsrrafactory in
the Javadoc index

Resource adapter

Example: Accessing data using IBM extended APIs for connections
Example: Accessing data using IBM extended APIs to share connections between container-managed and bean-managed persistence beans
Searchable topic ID:
cextiapi
Last updated: Jun 21, 2007 9:56:50 PM CDT
WebSphere Application Server for z/OS, Version 5.0.2
http://publib.boulder.ibm.com/infocenter/wasinfo/index.jsp?topic=/com.ibm.websphere.zseries.doc/info/zseries/ae/rdat_cextiapi.html