lazy loading in granite ds

Question

how will i load my entities in my flex application using lazy loading .I have a deep object graph

Answer 1

AFAIK it's impossible. You should have opened hibernate session to do this. In my project I'm doing what you need this way:

I have spring service like this:

public interface SomeObjectManager {
   List<SomeObject> getObjects();     // here we have lazy loading for SomeObject's properties
   SomeObject getFullObject(long objectId); // here we're loading full object
}

Some properties of SomeObject use lazy loading. To load them I use HQL query like this:

SELECT s FROM SomeObject s
   LEFT JOIN FETCH s.child children
      LEFT JOIN FETCH children.items items
         LEFT JOIN FETCH items.property
WHERE s.id=:id

This query forces hibernate to load properties defined lazy.

So if you don't need fully loaded SomeObject instances you use getObjects() method. If then you need details on concrete SomeObject instance you use getFullObject() method.

Hope this helps.

Answer 2

GraniteDS, together with its data management framework, lets you transparently load your uninitiated associations: see documentation here. So, basically, you don't have to do anything special in order to initialize your lazy collections/proxies, you only need to access one of them on the client side (asking for the size of a collection for example) and it will trigger a call to the server and fetch the uninitialized data.

If you don't want or can't use transparent lazy-loading, you need to write a specific initialization method which must have access to an EntityManager, receive your entity as a parameter, initialize the required association and send the entity back to the client.