code: private void addAssignments(MpxjTreeNode parentNode, ProjectFile file)
     {
        for (ResourceAssignment assignment : file.getResourceAssignments())
        {
           final ResourceAssignment a = assignment;
           MpxjTreeNode childNode = new MpxjTreeNode(a)
           {
              @Override public String toString()
              {
                 Resource resource = a.getResource();
                 String resourceName = resource == null ? "(unknown resource)" : resource.getName();
                 Task task = a.getTask();
                 String taskName = task == null ? "(unknown task)" : task.getName();
                 return resourceName + "->" + taskName;
              }
           };
           parentNode.add(childNode);
        }
     }
docs: Add assignments to the tree.
  
  @param parentNode parent tree node
  @param file assignments container