The e-Book progress

I was initially using google docs to write the e-book, but then was too lost in formatting the book, or proof reading it again and again. Also I could not update it using my phone, which is pretty much my hand held computer now. I was reading someone else's book online, when using the blog as an ebook sounded reasonable, so I've gone ahead and ported some chapters over to a new blog.

http://startupastartup.blogspot.com/

As of now the access is restricted, but if you want access, just comment to this post and I shall be glad to add you as a proof reader to my book.

DWR + Lazy Loading

Time immemorial, we are all aware about the famous lazy load exceptions in Hibernate. Using a detached object does not exactly hide us from the issue. We are using DWR in our application and found that when marshalling (or unmarshalling if you insist) a detached object to JSON, DWR was erratically trying to call a null (lazyly loaded) object, causing LazyLoadExceptions.

We did not want to use OpenSessionInViewFilter as it is evil (some day I'll post all the consolidated rantings as one). You can google and find a lot of info around it.

As a quick fix we did what one would first think of, "It's a demo, just eager load it!". Well the demo was over and now was the time to investigate a better solution, and we did find it.

It was no rocket science, the solution was available in front of us all along, we just did not look hard enough. When using DWR, there are BeanConverters available which are responsible for this marshalling process. There was one for Hiberante, called "hibernate3". http://directwebremoting.org/dwr/server/hibernate

The HibernateBeanConverter tries to avoid reading from un-initialized properties. (If you just want something that blindly reads everything then just use a plain BeanConverter).

Bingo, so when exporting a detached hibernate object to DWR, use type="hibernate3" and that should resolve the lazy load issues.