Extensions to data access APIs

If a single data access API does not provide a complete solution for the applications, use WAS extensions to achieve interoperability between both the JCA and JDBC APIs.

Applications that draw from diverse and complex resource management configurations might require use of both the Java EE Connector Architecture (JCA) API and the JDBC API. However, in some cases the JDBC model does not completely integrate with the JCA (even though full integration is a foundation of the JCA specification). These inconsistencies can limit data access options for an application that uses both APIs. WAS provides API extensions to resolve the compatibility issues.

For example:

Without the benefit of an extension, applications using both APIs cannot modify the properties of a shareable connection after making the connection request, if other handles exist for that connection. (If no other handles are associated with the connection, then the connection properties can be altered.) This limitation stems from an incompatibility between the connection-configuration policies of the APIs:

The Connector Architecture (JCA) spec supports relaying to the resource adapter the specific properties settings at the time you request the connection (using the getConnection() method) by passing in a ConnectionSpec object. The ConnectionSpec object contains the necessary connection properties used to get a connection. After you obtain a connection from this environment, the application does not need to alter the properties. The JDBC programming model, however, does not have the same interface to specify the connection properties. Instead, it gets the connection first, then sets the properties on the connection.

WAS provides the following extensions to fill in such gaps between the JDBC and JCA specifications:

• WSDataSource interface - this interface extends the javax.sql.DataSource class, and enables a component or an application to specify the connection properties through the WAS JDBCConnectionSpec class to get a connection.
  • getConnection(JDBCConnectionSpec) - this method returns a connection with the properties specified in the JDBCConnectionSpec class.

  • See see the WSDataSource API documentation topic (as listed in the API documentation index).

• JDBCConnectionSpec interface - this interface extends the com.ibm.websphere.rsadapter.WSConnectionSpec class, which extends the javax.resources.cci.ConnectionSpec class. The standard ConnectionSpec interface provides only the interface marker without any get() and set() methods. The WSConnectionSpec and the JDBCConnectionSpec interfaces define a set of get() and set() methods used by the WAS run time. This interface enables the application to specify all the essential connection properties in order to get an appropriate connection. We can create this class from the WebSphere WSRRAFactory class.

  See see the JDBCConnection API documentation topic (as listed in the API documentation index).

• WSRRAFactory class - this is a factory class for the WebSphere Relational Resource Adapter, which allows the user to create a JDBCConnectionSpec object or other resource adapter related object.

  See see the WSRRAFactory API documentation topic (as listed in the API documentation index).

• WSConnection interface - this is an interface that allows users to call WebSphere proprietary methods on SQL connections; those methods are:

  • setClientInformation(Properties props) - See the topic, Example: Setting the client information with the setClientInformation(Properties) API, for more information and examples of setting client information.

  • Properties getClientInformation() - This method returns the properties object that is set using setClientInformation(Properties). Note that the properties object returned is not affected by implicit settings of client information.

  • WSSystemMonitor getSystemMonitor() - This method returns the SystemMonitor object from the backend database connection if the database supports System Monitors. The backend database will provide some connection statistics in the SystemMonitor object. The SystemMonitor object returned is wrapped in a WebSphere object (com.ibm.websphere.rsadapter.WSSystemMonitor) to shield applications from dependency on any database vendor code. See com.ibm.websphere.rsadapter.WSSystemMonitor Java documentation for more information.

    The following code is an example of using the WSSystemMonitor class:

    import com.ibm.websphere.rsadapter.WSConnection;
    ... try{
      InitialContext ctx=new InitialContext();
      
    // Perform a naming service lookup to get the DataSource object.
      DataSource ds=(javax.sql.DataSource]ctx.lookup("java:comp/jdbc/myDS");
    } catch (Exception e) {;}
     WSConnection conn=(WSConnection)ds.getConnection(); WSSystemMonitor sysMon=conn.getSystemMonitor(); if (sysMon!=null) 
    // indicates that system monitoring is supported on the current backend database
      {
       sysMon.enable(true);
       sysMon.start(WSSystemMonitor.RESET_TIMES);
       
    // interact with the database
       sysMon.stop();
       
    // collect data from the sysMon object
      } conn.close();
    

    The WSConnection interface is part of the PLUGINS_ROOT/com.ibm.ws.runtime_6.1.0.jar file.

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Subtopics

Example: Using IBM® extended APIs for database connections
Example: Using IBM extended APIs to share connections between CMP beans and BMP beans

 

Related concepts

Relational resource adapters and JCA

 

Related information

http://www.ibm.com/support/docview.wss?rs=180&uid=swg27006921