@Override
  protected List<? extends ILookupRow<Long>> execCreateLookupRows() {
    IProjectService service = BEANS.get(IProjectService.class);
    List<LookupRow<Long>> rows = new ArrayList<>();
    for (List<Object> projectData : service.getHierarchicalProjectLookupData()) {
      Long projectId = (Long) projectData.get(0);
      String projectName = (String) projectData.get(1);
      String projectNumber = (String) projectData.get(2);
      
      LookupRow<Long> row = new LookupRow<Long>(projectId, projectName);
      HierarchicalProjectRowData bean = new HierarchicalProjectRowData();
      bean.setProjectNumber(projectNumber);
      row.withAdditionalTableRowData(bean);
      rows.add(row);
    }
    return rows;
  }
  
  public class HierarchicalProjectRowData extends AbstractTableRowData {

    private static final long serialVersionUID = -7729290938303347521L;
    public static final String projectNumber = "projectNumber";
    
    private String m_projectNumber;
    
    public String getProjectNumber() {
      return m_projectNumber;
    }
    
    public void setProjectNumber(String m_projectNumber) {
      this.m_projectNumber = m_projectNumber;
    }
  }

    // Info: cannot de-serialize 'additionalTableRowData' because it uses generic
    // JSON serialization. See JsonLookupRow#tableRowDataToJson - this shouldn't
    // be a problem because that data is only used in the proposal chooser

                              public HierarchicalProjectRowData getAdditionalTableRowData() {
					if(getLookupRow() == null) {
						return null;
					} else {
						HierarchicalProjectRowData rowData = (HierarchicalProjectRowData)getLookupRow().getAdditionalTableRowData();
						
						if(rowData == null) {
							Iterator<ILookupRow<Long>> resultLookupRows = getResult().getLookupRows().iterator();
							
							while(resultLookupRows.hasNext()) {
								ILookupRow<Long> lookupRow = resultLookupRows.next();
								
								if(lookupRow.getKey().equals(getValue())) {
									rowData = (HierarchicalProjectRowData)lookupRow.getAdditionalTableRowData();
									break;
								}
							}
						}
						
						return rowData;
					}
				}

				@Override
				protected void execChangedValue() {
					HierarchicalProjectRowData rowData = getAdditionalTableRowData();

					//TODO: your logic 
				}