code: public static ActivityStreamMessage from(final Event event) {
  
          final ActivityStreamMessage msg = new ActivityStreamMessage();
  
          msg.id = event.getIdentifier().getIRIString();
          msg.type = event.getTypes().stream().map(IRI::getIRIString)
              .map(type -> type.startsWith(AS.URI) ? type.substring(AS.URI.length()) : type)
              .collect(toList());
  
          msg.published = event.getCreated().toString();
  
          final List<String> actors = event.getAgents().stream().map(IRI::getIRIString).collect(toList());
          msg.actor = actors.isEmpty() ? null : actors;
  
          event.getInbox().map(IRI::getIRIString).ifPresent(inbox -> msg.inbox = inbox);
          event.getTarget().map(IRI::getIRIString).ifPresent(target ->
              msg.object = new EventResource(target,
                      event.getTargetTypes().stream().map(IRI::getIRIString).collect(toList())));
  
          return msg;
      }
docs: Populate a ActivityStreamMessage from an Event
  @param event The event
  @return an ActivityStreamMessage