We are planning to move our user interface to Flex as our applications needs that kind of user interface. To use flex, you have to expose your backend via Web Services (Java Remoting is out for us because of cost). However, our entire backend is Hibernate based and they cannot be simply returned back not only because of proxy serialization/deserialization issues but also, that serializing one object could serialize the entire database!

One solution is to use valueobjects and selectively populate them but I feel there must be a better solution.

I would like to know if others have faced this problem and how they have handled it.

Thanks!

You should not transmit your domain objects (hibernate objects) via webservices. In a typical Hibernate Object Model there is much data which is only used internally or is not necessary for the client. Note, that transferring data via web services is very inefficient, and you should only transfer data which is really needed by the client.

You have to define a separate object layer of DataTransfer Objects. Those DTOs can but need not have all properties of the domain objects. Here you can cut special associations that would otherwise cause the whole database to be transferred.

The advantage of this approach is much more flexibility and the client of the web-service is decoupled of your domain objects. This results in much cleaner system architecture. You can control effectively which data is transferred to the client.

The disadvantage is to spend additional time to create the DTOs and perform the mapping between the domain objects and the DTOs. But for this task there are many possibilities to create some generic mappers (which use reflection internally) that have to be written only once.