Lazy Load in a View?

Question

All,
I recentely completed initial development for a fairly complex, custom reporting component. As one might expect, it heavily uses SQL queries and a graph of objects in memory to render the various reports and search functionality available. The graph of objects can contain parent-child relationships up to five nesting levels deep. Not all reports and screens use all five nesting levels. In order to increase efficiency and lower the memory footprint, I implemented Lazy Load on these parent-child relationships.
My issue might just be a philosophical one. However, what I have ended up with is that a given JSP will initiate a Lazy Load as needed. For most model calculations and API usage, the Lazy Load simply is not required. So, the JSP ends up making these calls.
It seems a bit strange to have a JSP invoking operations that require database calls after the model has been returned to a view for dispatch.
Am I worrying overmuch about something not all that important? Or would you recommend moving this type of Lazy Load logic into the controller (we are using Struts) before dispatching the model to a given JSP?
- Saish

Answer 1

Not sure I completely understand what your solution was but I once designed a model that would do incremental 'lazy' loads.
The basic idea was to resolve an issue with downloading large amounts of data from before displaying anything. The model Objects were heirarchical (think tree) so we made it so that a the data was retrieved in parts and reassembled on the client. The top level items were retrieved first. So we would go ahead a display the top level Object while we were retrieving it's substructure in a background thread. As the user started digging down, a parent would block if it's child was not yet available.
The desired effect was that the users would not be aware of any delays. the server would tend to fill in the heirarchy faster than the user could expand it. Really fast users might catch up with it but would still benefit from at some level.
I left the company before I saw it go implemented but a competent developer did work on it (I don't know how much was revised) and my old boss told me that he asked that the design not be changed much and that the final result flew.
However this was for a 'fat' client. I'm not sure if this applies to your JSP situation. The basic point is that you can lazy load in the model and the gui doesn't have to know anything about it.