Research notes on basic relieving the Content Apps from tight JCR dependencies.

Major problems preventing Content Apps from being JCR-agnostic

• Action Executor API. We don't debate whether ActionExecutor should or should not be responsible for primary action availability checking , but it shouldn't do it _exclusively_ for javax.jcr.Items.
  
  • Should work over Vaadin Items. Being used in both Browser and Detail sub-apps of Content App it is probably the most severe blocker for the task.
  • Availability rules are all affected, but easy to fix, because those that depend on JCR can simply cast to JcrItemAdapter/JcrNodeAdapter.
  • Still not quite clear what to do with JCR logic inside AbstractActionExecutor itself.
• Serialization/de-serialization of item ids in to strings (basically - URL fragments).
  
  • URL fragment to item id transformation Expand source

    String itemId = null;
    try {
    	itemId = JcrItemUtil.getItemId(SessionUtil.getNode(workspaceName, path));
        // MGNLUI-1475: item might have not been found if path doesn't exist
        if (itemId == null) {
    		itemId = JcrItemUtil.getItemId(SessionUtil.getNode(workspaceName, workbenchRoot));
            BrowserLocation newLocation = getCurrentLocation();
            newLocation.updateNodePath("/");
            getAppContext().updateSubAppLocation(getSubAppContext(), newLocation);
        }
    } catch (RepositoryException e) {
    	log.warn("Could not retrieve item at path {} in workspace {}", path, workspaceName);
    }

• Mixed signatures of methods in Content App related presenters and events
  
  • Some operate over Vaadin Items, some - over the JcrItemAdapters, some, like aforementioned, - over JCR Items themselves. It sometimes leads to ItemId <-> Item conversion several times during delegation.
    
    • As a solution - only Item Ids should be used as a transferable during components/apps/sub-apps communication.
    • Only workbench knows how to transform Item Id into a Vaadin Item. Ideally - that should be a job of a separate datasource manager component as such functionality is need in various places (e.g. Detail Sub-apps).
  • Strings as Item ids everywhere - Object should be used instead ().