private void prepareTransUnitUpdatedEvent(
      int previousVersionNum, ContentState previousState, HTextFlowTarget target) {
    LocaleId localeId = target.getLocaleId();
    HTextFlow textFlow = target.getTextFlow();
    HDocument document = textFlow.getDocument();
    HProjectIteration projectIteration = document.getProjectIteration();
    String iterationSlug = projectIteration.getSlug();
    String projectSlug = projectIteration.getProject().getSlug();
    ProjectType projectType = projectIteration.getProjectType();

    WorkspaceId workspaceId =
        new WorkspaceId(new ProjectIterationId(projectSlug, iterationSlug, projectType), localeId);
    Optional<TranslationWorkspace> workspaceOptional =
        translationWorkspaceManager.tryGetWorkspace(workspaceId);
    if (!workspaceOptional.isPresent()) {
      return;
    }

    TransUnitTransformer transUnitTransformer =
        serviceLocator.getInstance(TransUnitTransformer.class);
    TransUnit transUnit = transUnitTransformer.transform(textFlow, target, target.getLocale());

    DocumentId documentId = new DocumentId(document.getId(), document.getDocId());
    int wordCount = textFlow.getWordCount().intValue();

    TransUnitUpdateInfo updateInfo =
        createTransUnitUpdateInfo(
            transUnit, documentId, wordCount, previousVersionNum, previousState);

    CacheValue context =
        updateContext.getIfPresent(new CacheKey(transUnit.getId(), transUnit.getLocaleId()));
    TransUnitUpdated updated;
    if (context != null) {
      updated = new TransUnitUpdated(updateInfo, context.editorClientId, context.updateType);
      log.debug("about to publish trans unit updated event {}", updated);
    } else if (ServletContexts.instance().getRequest() != null) {

      String sessionId = ServletContexts.instance().getRequest().getSession().getId();
      EditorClientId editorClientId = new EditorClientId(sessionId, -1);
      updated =
          new TransUnitUpdated(
              updateInfo, editorClientId, TransUnitUpdated.UpdateType.NonEditorSave);
    } else {
      updated =
          new TransUnitUpdated(
              updateInfo,
              new EditorClientId("unknown", -1),
              TransUnitUpdated.UpdateType.NonEditorSave);
    }
    if (Events.exists()) {
      Events.instance()
          .raiseTransactionSuccessEvent(
              TextFlowTargetUpdatedEvent.EVENT_NAME,
              new TextFlowTargetUpdatedEvent(workspaceOptional.get(), target.getId(), updated));
    }
  }