List users = new ArrayList();
List roleIds = workflowActivity.getPerformers();
int sizeRole = roleIds.size();
for (int i = 0; i < sizeRole; ++i)
{
WorkflowRole role = (WorkflowRole) userDatabase.findRole((String) roleIds.get(i));
Iterator userInterator = role.getParticipants();
while (userInterator.hasNext())
{
WorkflowParticipant user = (WorkflowParticipant) userInterator.next();
append2List(users, user);
}