Connection Wrapping

The following features pertain to connection wrapping:

• Wrapping Connections

• Obtaining a Physical Connection From a Wrapped Connection

• Using the Connection.unwrap() Method

Wrapping Connections

If the Wrap JDBC Objects option is true (the default), wrapped JDBC objects are returned for Statement, PreparedStatement, CallableStatement, ResultSet, and DatabaseMetaData.

This option ensures that Statement.getConnection() is the same as DataSource.getConnection(). Therefore, this option should be true when both Statement.getConnection() and DataSource.getConnection() are done.

You can specify the Wrap JDBC Objects option in the following ways:

• Check or uncheck the Wrap JDBC Objects box on the Edit Connection Pool Advanced Attributes page in the Administration Console. For more information, click the Help button in the Administration Console.

• Specify the ----wrapjdbcobjects option in the asadmin create-jdbc-connection-pool command. For more information, see the Oracle GlassFish Server 3.0.1 Reference Manual.

Obtaining a Physical Connection From a Wrapped Connection

The DataSource implementation in the GlassFish Server provides a getConnection method that retrieves the JDBC driver’s SQLConnection from the GlassFish Server’s Connection wrapper. The method signature is as follows:

public java.sql.Connection getConnection(java.sql.Connection con) 
throws java.sql.SQLException

For example:

InitialContext ctx = new InitialContext();
com.sun.appserv.jdbc.DataSource ds = (com.sun.appserv.jdbc.DataSource) 
   ctx.lookup("jdbc/MyBase");
Connection con = ds.getConnection();
Connection drivercon = ds.getConnection(con); //get physical connection from wrapper
// Do db operations.
// Do not close driver connection.
con.close(); // return wrapped connection to pool.

Using the Connection.unwrap() Method

If the JDK version 1.6 is used, the GlassFish Server supports JDBC 4.0 if the JDBC driver is JDBC 4.0 compliant. Using the Connection.unwrap() method on a vendor-provided interface returns an object or a wrapper object implementing the vendor-provided interface, which the application can make use of to do vendor-specific database operations. Use the Connection.isWrapperFor() method on a vendor-provided interface to check whether the connection can provide an implementation of the vendor-provided interface. Check the JDBC driver vendor's documentation for information on these interfaces.