public Timestamp getTimestamp(String columnName) throws SQLException {
        return getTimestamp(getColIdxByName(columnName));
    }
Retrieves the value stored in the designated column
of the current row as a <code>java.sql.Timestamp</code> object.

@param columnName a <code>String</code> object giving the SQL name of
       a column in this <code>CachedRowSetImpl</code> object
@return the column value; if the value is SQL <code>NULL</code>,
        the result is <code>null</code>
@throws SQLException if the given column name does not match one of
           this rowset's column names or the cursor is not on one of
           this rowset's rows or its insert row
src/main/java/org/replicadb/rowset/sun/rowset/CachedRowSetImpl.java