public class Item {
private String name;
private Set categories = new HashSet();
private Set bids = new HashSet();
private Bid successfulBid;
...
}
----------------------------------------------------
public class Bid {
...
private Item item;
...
}

-----------------------------------------------------
public class User {
private Address shippingAddress;
private Set billingDetails;
..
}

-----------------------------------------------------
public class Category {
private String name;
private Category parentCategory;
private Set childCategories = new HashSet();
private Set items = new HashSet();
..
}
-----------------------------------------------------



Considering Item, Bid, User, Category:
The usecase requirement is as follows:

USECASE 1 : Require item.successfulBid, item.categories.parentCategory
USECASE 2 : Require item.categories.childCategories
USECASE 3 : Require item.bid , item.user.shippingAddress, item.user.billingDetails
USECASE 4 : Require complete item (including it's associations and collections populated)

If i write a generic DAO method which will accept which all populated associations and collections of Item should be written...
Based on this input (and dynamic eager fetching), i will create a dynamic HQL which will fetch only the required data.


Item getItem(String itemId, Vector criteria){
//generate dynamic HQL using this criteria elements in fetch clause
}


So in:
UseCase1:
Vector criteria = new Vector(0,1);
criteria.add("item.successfulBid");
criteria.add("item.categories.parentCategory");
Item item = getItem(criteria);

UseCase2:
Vector criteria = new Vector(0,1);
criteria.add("item.categories.childCategories");
Item item = getItem(criteria);

UseCase3:
Vector criteria = new Vector(0,1);
criteria.add("item.bid");
criteria.add("item.user.shippingAddress");
criteria.add("item.user.billingDetails");
Item item = getItem(criteria);

UseCase4:
Vector criteria = new Vector(0,1);
criteria.add("*");
Item item = getItem(criteria);

Is this a good idea..? Comments plz..

If you call your Vector Criteria, why don't you use Criteria API then? If you don't have access to session at that part of your program, you could use a DetachedCriteria:

Yes.. either HQL fetch query or Criteria API..
but my main query was, Am i on right track.. Is this approach good as i have not seen this approach yet ..