validator for iteration name

As discussed, I really would consider other options before going this route. Nevertheless,

The operation he should be looking at is:

<project-operation id="com.ibm.team.process.server.saveProjectArea">

Here's some code to start with:

public class IterationSaveOperationParticipant extends AbstractService implements IOperationParticipant {

@Override
public void run(AdvisableOperation operation,
  IProcessConfigurationElement participantConfig,
  IParticipantInfoCollector collector, IProgressMonitor monitor)
  throws TeamRepositoryException {
 
 if (operation instanceof ProjectAreaSaveOperation)
 {
  ProjectAreaSaveOperation operationData = (ProjectAreaSaveOperation) operation;

  List<IProcessItem> savedItems = Arrays.asList(operationData.getSavedItems());
   for (IProcessItem savedItem : savedItems)
  {
   if (savedItem.getProcessItemType() == IProcessItem.ITERATION)
   {
    IRepositoryItemService itemService = getService(IRepositoryItemService.class);

    IIteration newIteration = (IIteration) savedItem;

   ...validate here newIteration.getName()...

I am getting tired to try to dig up the basic information necessary to understand the question and tend to not try to answer any more. It you want answers See How should I ask a question in the Forum if I want to receive useful answers? Most contributors here don't have the time to pry the info out of the asking user.

In general, it is possible to write process advisors. But you need an operation that you can use. I am not sure there is such an operation. These are the ones available: https://jazz.net/wiki/bin/view/Main/CustomPreconditionsTable#operations