Migrating applications that use the WSCallHelper interface to Liberty

WebSphere® Application Server traditional provides the now-deprecated WSCallHelper interface. Applications that use the associated proprietary APIs can be updated to use the standard Java™ Database Connectivity (JDBC) wrapper pattern.

About this task

In WebSphere Application Server traditional, applications use the WSCallHelper interface to access nonstandard vendor-specific JDBC APIs. For Liberty, use the JDBC wrapper pattern, which is a more standard JDBC specification-based approach. The wrapper pattern enables JDBC programmers to implement the Wrapper interface to access vendor-specific JDBC APIs safely in an application-server-managed environment. For the wrapper pattern to work, the JDBC driver must be compliant with the JDBC 4.0 or later specification level. To determine the JDBC specification level, consult your driver vendor.

Procedure

Implement the Wrapper interface isWrapperFor and unwrap methods to access vendor-specific JDBC APIs.

The following examples demonstrate how you can use the JDBC wrapper pattern to obtain a native Oracle connection or a native Oracle PreparedStatement object to call the nonstandard vendor-specific methods.

  • Obtain an oracle.jdbc.OracleConnection object.
    Context ic = new InitialContext();
DataSource ds = (DataSource)ic.lookup("jdbc/OracleDS");
Connection conn = ds.getConnection();

if (conn.isWrapperFor(oracle.jdbc.OracleConnection.class)) {
    oracle.jdbc.OracleConnection oraCon = conn.unwrap(oracle.jdbc.OracleConnection.class);
    // Do some vendor-specific work here.
}
conn.close();
  • Obtain an oracle.jdbc.OraclePreparedStatement object.
    Context ic = new InitialContext();
DataSource ds = (DataSource)ic.lookup("jdbc/OracleDS");
Connection conn = ds.getConnection();

PreparedStatement pstmt = conn.prepareStatement("SELECT 1 FROM DUAL");
if(pstmt.isWrapperFor(oracle.jdbc.OraclePreparedStatement.class)){
    oracle.jdbc.OraclePreparedStatement opstmt = pstmt.unwrap(oracle.jdbc.OraclePreparedStatement.class);
    // Do some vendor-specific work here.
}
pstmt.close();
conn.close();