Extract underlying Oracle connection from Jboss Wrapped connection, and create Oracle Clob Parameter

DbUtil.java

package com.bowerstudios.myapp.dao;

import java.io.Writer;
import java.sql.Connection;
import java.sql.SQLException;

import oracle.jdbc.OracleConnection;
import oracle.sql.CLOB;

import org.jboss.resource.adapter.jdbc.WrappedConnection;

public class DbUtil {

	public static OracleConnection oracleConnectionFromPoolConnection(Connection conn){
		if(conn instanceof OracleConnection){
			return (OracleConnection) conn;
		}else if(conn instanceof WrappedConnection){
			WrappedConnection wrappedConn = (WrappedConnection) conn;
			try {
				return (OracleConnection) wrappedConn.getUnderlyingConnection();
			} catch (SQLException e) {
				e.printStackTrace();
			} 
		}
			
		throw new RuntimeException("Cannot create OracleConnection from pooled datasource connection");
	}
	
	public static CLOB getCLOB(String xmlData, Connection conn) throws SQLException{
		conn = oracleConnectionFromPoolConnection(conn);
		
		CLOB tempClob = null;
		try{
		    // If the temporary CLOB has not yet been created, create one
		    tempClob = CLOB.createTemporary(conn, true, CLOB.DURATION_SESSION); 
		 
		    // Open the temporary CLOB in readwrite mode, to enable writing
		    tempClob.open(CLOB.MODE_READWRITE); 
		    // Get the output stream to write
		    Writer tempClobWriter = tempClob.getCharacterOutputStream(); 
		    // Write the data into the temporary CLOB
		    tempClobWriter.write(xmlData); 
		 
		    // Flush and close the stream
		    tempClobWriter.flush();
		    tempClobWriter.close(); 
		 
		    // Close the temporary CLOB 
		    tempClob.close();    
		  } catch(Exception exp){
		    if(tempClob!=null){
		    	tempClob.freeTemporary(); 
		    }
		    exp.printStackTrace();
		  }
		  return tempClob; 
		}

}

MyStoredProcedure.java

package com.bowerstudios.myapp.dao;

import java.math.BigDecimal;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Types;

import javax.sql.DataSource;

import org.apache.log4j.Logger;
/**
 * FUNCTION: F_MY_FUNCTION
 * ARGUMENTS: p_tracking_id: Tracking ID of document
 * p_xml: XML to submit
 * RETURN: The doc_id
 */
public class MyStoredProcedure {

	private static final Logger logger = Logger.getLogger(MyStoredProcedure.class);
	
	public static final String STORED_PROCEDURE_NAME = "{call ? := MYSCHEMA.PKG_MYPKG.F_MY_FUNCTION(?,XMLType(?))}";
	
	private DataSource ds;
	
	public MyStoredProcedure(DataSource ds){
		this.ds = ds;
	}

	public Long myFunction(Long trackingId, String xmlDoc){
		Long docId = null;
		
		Connection conn = null;
		
		try {
			conn = ds.getConnection();
			CallableStatement cs = conn.prepareCall(STORED_PROCEDURE_NAME);

			cs.registerOutParameter(1, Types.NUMERIC);
			
			if(trackingId==null){
				cs.setNull(2, Types.NUMERIC);
			}else{
				cs.setBigDecimal(2, new BigDecimal(trackingId));
			}
			cs.setObject(3, DbUtil.getCLOB(xmlDoc, conn));
			
			cs.execute();
			
			docId = cs.getLong(1);
			
		} catch (SQLException e) {
			logger.error("Error calling My Stored Procedure", e);
			
		}finally{
			if(conn !=null){
				try {
					conn.close();
				} catch (SQLException e) {
					logger.error("Error closing db connection after My Stored Procedure", e);
				}
			}
		}
		
		return docId;
	}
}