Currently working on an upgrade from richfaces 3.3 to 4.5. I am trying to migrate a class that was previously a SerializableDataModel and working to an ExtendedDataModel. The it seems to display correctly but when I do an ajax call on the row click event the rowKey is being set to null.

xhtml code:

<rich:dataTable id="trans"  value="#{modelMonitorAction}"
  width="100%" var="md" rowClasses="odd-row,even-row" styleClass="gfits-table"
  rendered="#{modelMonitorAction.rowDetailsCount > 0}" >
  <a4j:ajax event="rowclick" execute="@this"
  listener="#{mdDetailsAction.modelDetails(1, '',modelMonitorAction.selectedModel)}"
  render="mdDetails" >

ModelMonitorAction extends PageanatingDataModel.java:

public class PaginatingDataModel<Model, Integer> extends
  ExtendedDataModel<Model>{
  /** */
  private static final long serialVersionUID = 2954923950179861809L;
  /** */
  protected Integer currentPk;
  /** */
  protected boolean descending = true;
  /** */
  protected String sortField = getDefaultSortField();
  /** */
  protected boolean detached = false;
  /** */
  protected List<Integer> wrappedKeys = new ArrayList<Integer>();
  /** */
  private int rowCount = 0;
  /** */
  private int rowIndex;
  /** */
  protected Map<Integer, Model> wrappedData = new HashMap<Integer, Model>();
  /**
  * @see org.ajax4jsf.model.ExtendedDataModel#getRowKey()
  */
  @Override
  public Object getRowKey() {
  return currentPk;
  }
  /**
  * @see org.ajax4jsf.model.ExtendedDataModel#setRowKey(java.lang.Object)
  */
  @SuppressWarnings("unchecked")
  @Override
  public void setRowKey(Object key) {
  this.currentPk = (Integer) key;
  }
  /**
  * @see org.ajax4jsf.model.SerializableDataModel#update()
  */
  //Looks like this is doing sorting of some sort will fix once application deploys
// @Override
// public void update() {
// if (getSortFieldObject() != null) {
// final String newSortField = getSortFieldObject().toString();
// if (newSortField.equals(sortField)) {
// descending = !descending;
// }
// sortField = newSortField;
// }
// detached = false;
// }

  /**
  * @return Object
  */
  protected Object getSortFieldObject() {
  final FacesContext context = FacesContext.getCurrentInstance();
  final Object sortFieldObject = context.getExternalContext()
  .getRequestParameterMap().get("sortField");
  return sortFieldObject;
  }

  /**
  * @param sortField
  */
  public void setSortField(final String sortField) {

  if (this.sortField.equals(sortField)) {
  descending = !descending;
  } else {
  this.sortField = sortField;
  }
  }
  /**
  * @return String
  */
  public String getSortField() {
  return sortField;
  }


  public void updateSortField(){
  if (getSortFieldObject() != null) {
  final String newSortField = getSortFieldObject().toString();
  if (newSortField.equals(sortField)) {
  descending = !descending;
  }
  sortField = newSortField;
  }
  detached = false;
  }
  /**
  * @see javax.faces.model.DataModel#setRowIndex(int)
  */
  @Override
  public void setRowIndex(int arg0) {
  // TODO Auto-generated method stub
  //throw new UnsupportedOperationException();
  rowIndex = arg0;
  return;
  }
  /**
  * @see javax.faces.model.DataModel#setWrappedData(java.lang.Object)
  */
  @Override
  public void setWrappedData(final Object data) {
  throw new UnsupportedOperationException();
  }
  /**
  * @see javax.faces.model.DataModel#getRowIndex()
  */
  @Override
  public int getRowIndex() {
  // TODO Auto-generated method stub
  //throw new UnsupportedOperationException();
  return rowIndex;
  }
  /**
  * @see javax.faces.model.DataModel#getWrappedData()
  */
  @Override
  public Object getWrappedData() {
  throw new UnsupportedOperationException();
  }

  public void wrap(FacesContext context, DataVisitor visitor, Range range, Object argument, List<Model> list) throws IOException
  {
  wrappedKeys = new ArrayList<Integer>();
  wrappedData = new HashMap<Integer, Model>();
  for (Model row : list)
  {
  Integer id = getId(row);
  setRowKey(id);
  wrappedKeys.add(id);
  wrappedData.put(id, row);
  visitor.process(context, id, argument);
  }
  }

  @Override
  public void walk(FacesContext context, DataVisitor visitor, Range range, Object argument)
  {
  if(validate()) {
  setRowCount(0);
  return;
  }

  int firstRow = ((SequenceRange) range).getFirstRow();
  int maxResults = ((SequenceRange) range).getRows();
  if (detached && getSortFieldObject() != null) {
  for (final Integer key : wrappedKeys) {
  setRowKey(key);
  visitor.process(context, key, argument);
  }
  } else {
  String sortField = getSortField();

  try {
  wrap(context, visitor, range, argument, findObjects(firstRow, maxResults, sortField, descending));
  } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
  }
  }
  }
  /**
  * @see javax.faces.model.DataModel#isRowAvailable()
  */
  @Override
  public boolean isRowAvailable() {
  if (currentPk == null) {
  return false;
  }
  if (wrappedKeys.contains(currentPk)) {
  return true;
  }
  if (wrappedData.entrySet().contains(currentPk)) {
  return true;
  }
  try {
  if (getObjectById(currentPk) != null) {
  return true;
  }
  } catch (final Exception e) {
  }
  return false;
  }
  /**
  * @see javax.faces.model.DataModel#getRowData()
  */
  @Override
  public Model getRowData() {
  if (currentPk == null) {
  return null;
  } else {
  Model ret = wrappedData.get(currentPk);
  if (ret == null) {
  ret = this.getObjectById(currentPk);
  wrappedData.put(currentPk, ret);
  return ret;
  } else {
  return ret;
  }
  }
  }
  /**
  * @see javax.faces.model.DataModel#getRowCount()
  */
  @Override
  public int getRowCount() {
  if (rowCount == 0) {
  rowCount = getNumRecords();
  }
  return rowCount;
  }
  /**
  * @param rowCount
  */
  public void setRowCount(int rowCount) {
  this.rowCount = rowCount;
  }
  /**
  *
  * @param object
  * @return U
  */
  public Integer getId(Model object) {
  return null;
  }
  public boolean validate(){
  return false;
  }
  /**
  * @param firstRow
  * @param numberOfRows
  * @param sortField
  * @param descending
  * @return List<T>
  */
  public List<Model> findObjects(int firstRow,
  int numberOfRows, String sortField, boolean descending){
  return null;
  }
  /**
  * @param id
  * @return T
  */
  public Model getObjectById(Integer id){
  return null;
  }
  /**
  * @return String
  */
  public  String getDefaultSortField(){
  return null;
  }
  /**
  * @return int
  */
  public int getNumRecords(){
  return 0;
  }

}

Can anyone see anything obvious I am doing wrong or forgetting? This is my first experience using the ExtendedDataModel. Also if anybody could just point me to a good tutorial on how to use it that would be much appreciated.