Mapping Oracle XMLType to DOM4J Element

XML type representation for Hibernate can be mapped to DOM4J Element type. Implementation will be based on Oracle Drivers Only. This example provides a simple implementation that will work on weblogic platform or with plain simple oracle connections.

The idea is to be able to create simple realtional-xml databases. By using a XML type the finders can use XPath and search troughout the XMLTypes. This is a very powerfull concept as it combines the relational and XML based structures into one simple XML-Relational database.

package mypackage;
....

public class HibernateXMLType implements UserType ,Serializable{
.....

/*

     * (non-Javadoc)

     * 

     * @see net.sf.hibernate.UserType#nullSafeGet(java.sql.ResultSet,

     *      java.lang.String[], java.lang.Object)

     */

    public Object nullSafeGet( ResultSet rs, String [ ] names, Object arg2 ) throws HibernateException, SQLException {

        OracleResultSet ors = null;

        if ( rs instanceof weblogic.jdbc.wrapper.ResultSet ) {

            ors = (OracleResultSet) getNativeResultSet ( rs );

        } else if ( rs instanceof OracleResultSet ) {

            ors = (OracleResultSet) rs;

        } else {

            throw new UnsupportedOperationException (

                    "Only direct support for Weblogic and Oracle drivers. Please check your pool driver." );

        }

        OPAQUE op = ors.getOPAQUE ( names[0] );

        oracle.xdb.XMLType xt = oracle.xdb.XMLType.createXML ( op );

        DOMReader reader = new DOMReader ();

        org.dom4j.Document document = reader.read ( xt.getDOM () );

        return document.getRootElement ();// getClobVal();

    }

    /*

     * (non-Javadoc)

     * 

     * @see net.sf.hibernate.UserType#nullSafeSet(java.sql.PreparedStatement,

     *      java.lang.Object, int)

     */

    public void nullSafeSet( PreparedStatement st, Object value, int index ) throws HibernateException, SQLException {

        String conName = "";

        try {

            OraclePreparedStatement ost = null;

            if ( st instanceof OraclePreparedStatement ) {

                ost = (OraclePreparedStatement) st;

            } else {

                throw new HibernateException ( "PreparedStatement object must be a OraclePreparedStatement !! "

                        + "Connection class is " + st.getClass ().getName () );

            }

            Connection conn = st.getConnection ();

            conName = conn.getClass ().getName ();

            // Get the oracle connection class for checking

            Class oracleConnectionClass = Class.forName ( "oracle.jdbc.driver.OracleConnection" );

            // Make sure connection object is right type

            if ( !oracleConnectionClass.isAssignableFrom ( conn.getClass () ) ) {

                if ( conn instanceof PoolConnection ) {

                    try {

                        conn = getNativeConnection ( st.getConnection ().getMetaData ().getConnection () );

                        if ( !oracleConnectionClass.isAssignableFrom ( conn.getClass () ) ) {

                            throw new HibernateException (

                                    "JDBC connection object must be a oracle.jdbc.OracleConnection !! "

                                            + "Connection class is " + conn.getClass ().getName () );

                        }

                    } catch ( Exception sEx ) {

                        throw new HibernateException (

                                "JDBC connection object must be a oracle.jdbc.OracleConnection !! "

                                        + "Connection class is " + conn.getClass ().getName () );

                    }

                } else

                    throw new UnsupportedOperationException (

                            "Only direct support for Weblogic and Oracle drivers. Please check your pool driver." );

            }

            if ( oracleConnectionClass.isAssignableFrom ( conn.getClass () ) ) {

                ost.setOPAQUE ( index, oracle.xdb.XMLType.createXML ( conn, ( (Element) value ).asXML () ) );// (OPAQUE)

            } else {

                throw new HibernateException ( "JDBC connection object must be a oracle.jdbc.OracleConnection !! "

                        + "Connection class is " + conn.getClass ().getName () );

            }

        } catch ( SQLException e ) {

            e.printStackTrace ();

            throw e;

        } catch ( HibernateException e ) {

            e.printStackTrace ();

            throw e;

        } catch ( ClassCastException e ) {

            e.printStackTrace ();

            // could not find the class with reflection

            throw new HibernateException ( "Unable to case a required class.\n" + e.getMessage () + "  -- value class:"

                    + conName );

        } catch ( ClassNotFoundException e ) {

            // could not find the class with reflection

            throw new HibernateException ( "Unable to find a required class.\n" + e.getMessage () );

        }

    }

....
}

Have fun....

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