Detached criteria - refine search - remove restriction

javatwo · **Joined:** Tue Sep 13, 2005 2:01 am **Posts:** 137

Hi,

I am using DetachedCriteria. After a user builds a DetachedCriteria using query form, and click search, a list of search results show up. Above the search results, user can further refine results by selecting a property value.

For example, color: black, yellow, red.

I need an API to remove a restriction(eg, color) from a detached criteria, then I can set color to different value.

However, DetachedCriteria does not have such a method.
Any idea are appreciated.

Thanks!
Dave

roy_tate · **Joined:** Wed Mar 07, 2007 5:15 pm **Posts:** 2

My advise would be to create a wrapper class that collects a list of Criterion and a list of Order elements, and build a DetachedCriteria when you are ready for a search. If your Criterion were in a dictionary, a map, some associative collection, or even an ArrayList, you could replace or remove elements easily.

Code:

class MyCriteriaBuilder 
{
  void AddCriterion(Criterion) ...
  void RemoveCriterion(string propertyname) ...
  void AddOrder(Order) ...
  void RemoveOrder(string propertyname) ...
  DetachedCriteria CreateDetachedCriteria() ...
}

javatwo · **Joined:** Tue Sep 13, 2005 2:01 am **Posts:** 137

Thanks for idea.
But my case is very complicated, with OR/Add and alias in the criteria.

If I can make a copy of a DetachedCriteria, it can solve the problem.

is DetachedCriteria.clone() a deep clone?
Thanks!

roy_tate · **Joined:** Wed Mar 07, 2007 5:15 pm **Posts:** 2

Well, the next idea would be to create a MutableDetachedCriteria that is a copy of DetachedCriteria as well as a MutableCriteriaImpl with expression and order removal methods. Once you have a MutableCriteriaImpl, you can implement the methods that I suggested earlier.

Really, I would not recommend this approach. I would recommend a business-case specific class [OrderHistoryFinder] that contains nullable fields, and allows you to get and set them with properties. This class would be responsible for building a DetachedCriteria on request. This would allow you to incorporate the logic for AND, OR, EXISTS, NOT EXISTS, etc. in a correct fashion. Here is a blog link that you should read.

http://www.ayende.com/Blog/archive/2006/12/07/7055.aspx

Good luck!

Roy