Number and names of columns from ODA MySQL stored procedure data set coded in Java?

I have generated Java code that can set up a dynamically created data set from a MySQL stored procedure source.
The data from the data set is plotted with a chart, again scripted in Java.
 
The problem is that to do the binding I need to know how many columns there are.
That info is dynamic, it changes from one plot to the next. If I cheat and tell my code the number of columns to expect I can get it all to work.
 
I've searched both the "Field Guide" & "Integrating and Extending BIRT" books, but I find they don't explain things very well.
I've also searched the web and found a bunch of code to play with but no luck so far.
Here's my latest bit of experimental code to try to do it, but my logging (using Eclipsec) shows odaResultSetColumns as always null.
 
How and when does odaResultSetColumns get populated?
 
For data sets created in the normal GUI way I can get the column names by iterating through reportDesignHandle.getDataSets().get(set_count).getPropertyIterator() and testing the structures, but that info again is not available in the dynamic case.
 
Can the binding be deferred to a later event where the data set info appears?
<pre class="_prettyXprint">
/**
* This method is called from the onPrepare method for a label in my BIRT rptdesign.
* Used on the MySQL stored procedure that gets the plot data.
* The data set is dynamically created and everything works fine (data set being read and a chart plotted) so long as I know "y_count" a priori.
* TODO Set y_count by dynamically counting the number of columns in the JDBC result set from the MySQL stored procedure call (where resultSetNumber = 2 i.e. the second result set).
* Once I have y_count I can set up the binding between the data set and the chart.
* Returns the number of y sequence columns.
*/
public int extractColumnInfo() throws Exception {

int y_count = 3;

// Fetching list of all data sets in the report.
@SuppressWarnings("unchecked")
ArrayList<OdaDataSetHandle> odaDataSetHandles = (ArrayList<OdaDataSetHandle>) reportDesignHandle.getAllDataSets();
System.out.println("odaDataSetHandles " + odaDataSetHandles);
for (OdaDataSetHandle odaDataSetHandle : odaDataSetHandles) {
OdaDataSet odaDataSet = (OdaDataSet) odaDataSetHandle.getElement();
System.out.println("odaDataSet.getName() " + odaDataSet.getName());
if (odaDataSet.getName().contentEquals(dataSetName_s)) { // private String dataSetName_s = "Sequence info";

dataSetImpl = SimpleElementFactory.getInstance().createDataSet( odaDataSetHandle );
List colList = dataSetImpl.getCachedResultSetColumns();
System.out.println("colList " + colList);
// CURRENTLY colList IS ALWAYS null.

@SuppressWarnings("unchecked")
ArrayList<OdaResultSetColumn> odaResultSetColumns = (ArrayList<OdaResultSetColumn>) odaDataSet.getLocalProperty(reportDesignHandle.getModuleHandle().getModule(), DataSetHandle.RESULT_SET_PROP);
System.out.println("odaResultSetColumns " + odaResultSetColumns);
// CURRENTLY odaResultSetColumns IS ALWAYS null.

PropertyHandle resultSet;
resultSet = odaDataSetHandle.getPropertyHandle(DataSetHandle.RESULT_SET_PROP);
System.out.println("resultSet " + resultSet);
System.out.println("resultSet.getContents() " + resultSet.getContents());

if (odaResultSetColumns != null) {
for (OdaResultSetColumn odaResultSetColumn : odaResultSetColumns) {
System.out.println("odaResultSetColumn.getColumnName() " + odaResultSetColumn.getColumnName());
System.out.println("odaResultSetColumn.getDataType() " + odaResultSetColumn.getDataType());

// Code examples from the web typically proceed like this.
// N.B. I don't want to set these. I want to acquire the column names used in my dynamically created ODA data set so I can count them.
// odaResultSetColumn.setColumnName("SOME_COLUMN_NAME");
// odaResultSetColumn.setNativeName("SOME_COLUMN_NAME");
// odaResultSetColumn.setDataType("integer");
// odaResultSetColumn.setPosition(1);
// odaResultSetColumn.setNativeDataType(4);
// resultSet.addItem(odaResultSetColumn);
//
// // The same thing with columnHints.
// ColumnHint resultHint = new ColumnHint();
// resultHint.setProperty(ColumnHint.COLUMN_NAME_MEMBER, "EMPLOYEENUMBER");
// resultHint.setProperty(ColumnHint.COLUMN_NAME_MEMBER, "integer");
// odaDataSetHandle.getPropertyHandle(DataSetHandle.COLUMN_HINTS_PROP).addItem(resultHint);
//
// //reportDesignHandle.getDataSets().add(dataSet);
}
}
}
}
return (y_count);
}
//

// Various chunks of code from the web that I've tried
//

// Connection conn = DriverManager.getConnection("jdbc:mysql://myURL:myPORT/sim", "sim", "");
// System.out.println("Got Connection.");
// Statement st = conn.createStatement();
// st.executeUpdate("");
//
// ResultSet rsColumns = null;
// DatabaseMetaData meta = conn.getMetaData();
// rsColumns = meta.getColumns(null, null, null, null);
// while (rsColumns.next()) {
// System.out.println(rsColumns.getString("TYPE_NAME"));
// System.out.println(rsColumns.getString("COLUMN_NAME"));
// }
// st.close();
// conn.close();
//

// private static void extractColumnInfo(OdaDataSetHandle odaDataSetHandle) throws Exception {
// // Cannot figure out how to make this following code work.
// // I want to see if we have a working handle to the stored procedure call data set.
//
// int rowcount = 0;
// // Configure the Engine and start the Platform.
// DesignConfig config = new DesignConfig();
//
// config.setBIRTHome("C:/birt/birt-runtime-2_6_1/birt-runtime-2_6_1/ReportEngine");
// IDesignEngine engine = null;
//
// OdaDataSourceDesign odaDataSource;
// DataEngineContext some_c = null;
// DataEngine de = DataEngine.newDataEngine(runnable.getReportEngine().getConfig(), some_c);
//
// de = DataEngine.newDataEngine(config, null);
// de.defineDataSource(odaDataSource);
// //de.defineDataSource(dsHandle_2.getDesign());
// de.defineDataSet(odaDataSetHandle.getElement());
// //de.defineDataSet(reportDesignHandle.getDataSets().get(set_count));
//
// QueryDefinition queryDefinition = new QueryDefinition();
// queryDefinition.setDataSetName(odaDataSetHandle.getElement().getName());
// //queryDefinition.setDataSetName(reportDesignHandle.getDataSets().get(set_count).getName());
// queryDefinition.setAutoBinding(true);
//
// IPreparedQuery pq = de.prepare(queryDefinition);
// IQueryResults qr = pq.execute(null);
//
// org.eclipse.birt.data.engine.api.IResultIterator ri = qr.getResultIterator();
// int cc = ri.getResultMetaData().getColumnCount();
// IResultMetaData rsmd = ri.getResultMetaData();
//
// while (ri.next()) {
// for (int i = 0; i < cc; i++)
// System.out.print(ri.getValue(rsmd.getColumnName(i + 1)) + " ");
// System.out.println("");
// rowcount++;
// }
// System.out.println("rowcount: " + String.valueOf(rowcount));
//
// ri.close();
// qr.close();
// de.shutdown();
// }
//

// int colNum = colList.size();
// var mytable = rC.getDesignHandle().findElement(dataSetName_s);
// try{itr= colList.iterator();
// colNr = 0;
// while(itr.hasNext()){
// col = itr.next();
// colname = col.getName(); // skip column from sourceTable
// if(colname.equals("Row ID")){continue;}
// // the first column should be just overwritten
// // this way we can define the format in the layout
// // unfortunately I still don't know how to do that one...
// if(colNr == 0){
// } else { // insert column to the right (1) mytable.insertColumn(colNr,1);
// datacell = mytable.getDetail().get(0).getCells().get(colNr );
// var newdata = reportDesignHandle.getDesignHandle().getElementFactory().newDataItem( colname );
// newdata.setResultSetColumn( colname );
// datacell.getContent().add(newdata);
// var myHeader = mytable.getHeader().get(0).getCells().get(colNr);
// var newlabel = reportDesignHandle.getDesignHandle().getElementFactory().newLabel( null );
// newlabel.setText( colname );
// myHeader.getContent().add(newlabel);
// }
// colNr ++;
// }
// }catch(err){}
//

//Bind data set to table
//rptTable.setProperty(IReportItemModel.DATA_SET_PROP, "Data Set"); //Bind data set to table
// String columnNamesArray[]; //Set name array
// Iterator iterator = odaDataSetHandle.getListProperty(DataSetHandle.RESULT_SET_PROP).iterator(); //Get data set iterator
// while (iterator.hasNext()) { //Loop through data set
// rsHandle = iterator.next(); //Set next handle
// columnNamesArray.push(rsHandle.getColumnName()); //Add column name to array
// col = StructureFactory.createComputedColumn(); //Create an empty computed column structure
// col.setName(rsHandle.getColumnName()); //Set the column name
// col.setExpression("dataSetRow[\"" + rsHandle.getColumnName() + "\"]"); //Set the expression
// rptTable.getColumnBindings().addItem(col); //Add column binding to table
// }
//

</pre>

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