Custom Type Handler question

[Ken Katsma]

Hi,

My group is currently using stored procedures in Oracle for all our
database access.  To get around the n+m problem we are considering
several alternatives.  One we know will work is to do a user function
for each column that maps to a "m" table that gives us the data in
string format (name,value pairs).

Another approach, (which we would prefer) is to return the results for
each "m" column as a cursor.  I can do this in java with code that looks
something like this:

class RefCursor
{

public static void main (String args [])
throws SQLException, ClassNotFoundException
{
  String query  = "begin "+
                       "open ? for "+
                       "'select dname, CURSOR(select ename "+
                                               "from emp "+
                                              "where
emp.deptno=dept.deptno) "+
                          "from dept'; "+
                   "end;";

  DriverManager.registerDriver
       (new oracle.jdbc.driver.OracleDrive

r());

  Connection conn=
      DriverManager.getConnection
      ("jdbc:oracle:thin:@aria-dev:1521:ora817dev",
        "scott", "tiger");

  Statement trace = conn.createStatement();

  CallableStatement  cstmt = conn.prepareCall(query);

  cstmt.registerOutParameter(1,OracleTypes.CURSOR);
  cstmt.execute();

  ResultSet rset= (ResultSet)cstmt.getObject(1);

  for(int i = 0;  rset.next(); i++ )
  {
   System.out.println( rset.getString(1) );
   ResultSet rset2 = (ResultSet)rset.getObject(2);
   for( int j = 0; rset2.next(); j++ )
       System.out.println ( "   " + rset2.getString(1) );
   rset2.close();

  }

  rset.close();
  cstmt.close();
}
}

To get the same functionality in iBatis we tried writing a custom type
handler for the cursor column that looks like this:

import java.sql.Ref;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.ibatis.sqlmap.client.extensions.ParameterSetter;
import com.ibatis.sqlmap.client.extensions.ResultGetter;
import com.ibatis.sqlmap.client.extensions.TypeHandlerCallback;
import com.ibatis.sqlmap.engine.type.ResultGetterImpl;

/**
* @author S001027
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class RefTypeHandler implements TypeHandlerCallback {

   /* (non-Javadoc)
    * @see
com.ibatis.sqlmap.client.extensions.TypeHandlerCallback#setParameter (com.ibatis.sqlmap.client.extensions.ParameterSetter,
java.lang.Object)
    */
   public void setParameter(ParameterSetter arg0, Object arg1)
           throws SQLException {
       if (arg1 != null)
       {
           arg0.setObject(arg1);
       }
   }

   /* (non-Javadoc)
    * @see
com.ibatis.sqlmap.client.extensions.TypeHandlerCallback#getResult(com.ibatis.sqlmap.client.extensions.ResultGetter )
    */
   public Object getResult(ResultGetter arg0) throws SQLException {
       System.out.println("Object: " +
arg0.getObject().getClass().getName());
       ResultSet result = (ResultSet) arg0.getObject();
       System.out.println("Iterating");
       while(result.next())
           System.out.println("test");
       result.close();

       return result;
   }

   /* (non-Javadoc)
    * @see
com.ibatis.sqlmap.client.extensions.TypeHandlerCallback#valueOf(java.lang.String)
    */
   public Object valueOf(String arg0) {
       // TODO Auto-generated method stub
       return null;
   }

Unfortunately, when the statement:

ResultSet result = (ResultSet) arg0.getObject();

executes, we get an error from oracle that says "FETCH OUT OF
SEQUENCE".  Is there something with the cursor going on in iBatis that
prevents us from touching the nested cursor?  I guess my next step is to
start stepping through the iBatis code in debug to see whats happening,
but I was hoping somebody may already have a solution or know the problem.

Thanks,

Ken