Point pp = new Point();
pp.x = -5;
pp.y = 1;
rport.getFigure().setLocation(pp);

public class CustomRequest extends Request {
	public CustomRequest(Object type) {
		super.setType(type);
	}
}

protected void handleNotificationEvent(Notification notification) {
...
performRequest(new CustomRequest(RequestConstantsCustom.REQ_REPOSITION_PORTS));
...
}

public void performRequest(CustomRequest request) {
        if (RequestConstantsCustom.REQ_REPOSITION_PORTS.equals(request.getType())) {
            //allowed, continue
        	 Command command = this.getCommand(request);
             if (command != null) {
            	 System.out.println("Executing mine custom command");
                 getDiagramEditDomain().getDiagramCommandStack().execute(
                     command);
                 return;
             }
        } else {
        	Request r = (Request) request;
        	super.performRequest(r);
        }
}

public Command getCommand(CustomRequest _request) {
	System.out.println("My Custom request...... "+_request.getType());
	Command command = new PortRepositionCommand(this);
	return command;
}

public class PortRepositionCommand extends Command {
...
	public PortRepositionCommand(XFunctionEditPart xFunctionEditPart) {
		editPart = xFunctionEditPart;
	}

	public void execute() {
		List l = editPart.getChildren();
		for (int i = 0; i < l.size(); i++) {
			if (l.get(i) instanceof RequiredPortEditPart) {
				RequiredPortEditPart rport = (RequiredPortEditPart) l.get(i);
				Point point = rport.getLocation();
			}
			else if (l.get(i) instanceof ProvidedPortEditPart){
				ProvidedPortEditPart rport = (ProvidedPortEditPart) l.get(i);
				Point pp = new Point();
				pp.x = 0;
				pp.y = 0;
				rport.getFigure().setLocation(pp);
			}
		}
	}
}