Hi all,
we're aiming at a Client/Server application based on EMF. In this szenario, we would like to view "Contracts" that have a HUGE number of "ContractItems". Fortunatly, in most cases users only want to see "Contract" and don't care about "ContractItems".

In order to reduce system load we decided to lazily load "ContractItems". For this we saw two sollutions:

1) On the server, instantiate Contract and all ContractItems. Put the contract in one resource and the items in the other resource. Serialize the ContractResource and return it to the client.. The client recieves a list with proxies. When resolving the first proxy it loads the resource with all ContractItems into its local ResourceSet. Further proxy resolution uses this resources and does not need server interaction anymore.

2) Make an "intermediate node" in the EMF model that "contains" the ContractItems. On the initial request for the "Contract" data, build this intermediate node, link it to the "Contract" node and put both into seperate resources. Seralilize the ContractResource and return it to the client. The client receives a "Contract" node with a proxy to the "intermediate" Node. When resolving this proxy, the server fills the intermediate node with all ContractItems and returns it to the client.

Solution 1) requires data access for each ContractItem even on the initial request, even when only Contract information is required; this is overhead.

Solution 2) introduces an "intermediate node" just for Client/Server (=ProxyResolving) purpose which should not be part of a Domain Model.
[Solution 2 can be amended by "hiding" the intermediate node using a derived relation on the Contract node into the ContractItems that gets the intermediate node's relation, thereby resolving the intermediate node's proxy. Still, the ecore model has to provide the intermediate node]

The Question

Is there a more satisfying solution?

(It would probably require references to have a URI. If this were the case, the whole list can be proxied (=1 Proxy) instead of being a List of Proxies (=n proxies).

Kind regards
Bernhard