Use of net.sf.hibernate.Criteria for querying

gpani · **Posted:** Fri Apr 02, 2004 11:06 am

I posted this question under the miscellaneous forum and maybe it belongs in the Beginners forum instead.

I am using Hibernate 2.1.2 with Resin 2.1.12 on SAPDB 7.4.

I have been trying to stay away from HQL as much as possible and accomplish as much as I can using Criteria. I have an object that has the following structure.

Code:

public class UserGroupFunction 
{ 
  ... 
  private UserGroup userGroup = null; 
  private Function function = null; 
  ... 
} 

public class UserGroup 
{ 
  private Long userGroupId = null; 
  ... 
} 

private class Function 
{ 
  private Long functionId = null; 
  private String functionName = ""; 
  private String functionUrl = ""; 
} 

The mappings in UserGroupFunction are as follows:

In the search() method in my DAO, I would like to accomplish two conditionals.

1. WHERE function.functionUrl IS NOT NULL
2. ORDER BY function.functionName

I tried to do it with the following code (out of desparation) but obviously it was too stupid and didn't work.

Code:

criteria.add(Expression.not(Expression.eq("function.functionUrl", null))); 
criteria.addOrder(Order.asc("function.functionName")); 

Is there any way to set conditions based on attributes within an object contained in the persistent object using the Criteria method or do I have to resign myself to doing this with HQL?

TIA

gpani · **Posted:** Fri Apr 02, 2004 5:57 pm

Is there any additional information that I can provide to clarify my question? If it is very rudimentary, could someone point me towards a source where I can research it further? I can't find anything on Google or in sample applications.

christian · **Posted:** Fri Apr 02, 2004 6:03 pm

Code:

critOne = s.createCriteria(UserGroupFunction.class);

critTwo = critOne.createCriteria("function").add(Expression.not(Expression.eq("functionUrl", null)));

critTwo.addOrder(Order.asc("functionName"));

gpani · **Posted:** Mon Apr 05, 2004 6:29 pm

Christian,

Thanks for the response. I tried to create a second criteria using the original criteria to order by functionName of the parentFunction. Any suggestions?

Code:

hibernateSession = HibernateManager.currentSession();
Criteria criteria = hibernateSession.createCriteria(FunctionRelation.class);

if (requestFunctionRelation.getParentFunction() != null)
{
  criteria.add(Expression.eq("parentFunction", requestFunctionRelation.getParentFunction()));
}
if (requestFunctionRelation.getChildFunction() != null)
{
  criteria.add(Expression.eq("childFunction", requestFunctionRelation.getChildFunction()));
}

Criteria functionCriteria = criteria.createCriteria("parentFunction");
functionCriteria.addOrder(Order.asc("functionName"));

functionRelationList = functionCriteria.list();

The following is the Exception stack trace

Code:

Stack Trace: java.lang.UnsupportedOperationException: subcriteria cannot be ordered
   at net.sf.hibernate.impl.CriteriaImpl$Subcriteria.addOrder(CriteriaImpl.java:75)
   at com.foo.bar.dao.site.access.FunctionRelationDAO.search(Unknown Source)
   at com.foo.bar.control.site.access.admin.FunctionRelationAdminAction.view(Unknown Source)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:324)
   at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:280)
   at org.apache.struts.actions.LookupDispatchAction.execute(LookupDispatchAction.java:252)
   at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
   at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
   at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
   at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:126)
   at javax.servlet.http.HttpServlet.service(HttpServlet.java:103)
   at com.caucho.server.http.FilterChainServlet.doFilter(FilterChainServlet.java:96)
   at com.caucho.server.http.Invocation.service(Invocation.java:315)
   at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
   at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
   at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
   at java.lang.Thread.run(Thread.java:534)

christian · **Posted:** Mon Apr 05, 2004 6:33 pm

Use HQL.

gpani · **Posted:** Mon Apr 05, 2004 6:35 pm

christian wrote:

Use HQL.

I think that would be the easiest option. I'll go ahead and do that. I was just wondering if it would've been possible with Criteria.

On a different note, are there any plans to improve on the Criteria API to make it as mature as HQL in future releases?

drbeta · **Posted:** Mon Apr 05, 2004 6:56 pm

gpani wrote:

christian wrote:

Use HQL.

I think that would be the easiest option. I'll go ahead and do that. I was just wondering if it would've been possible with Criteria.

On a different note, are there any plans to improve on the Criteria API to make it as mature as HQL in future releases?

Ordering by nested objects using the crit-api is still under development. Gavin once psoted that it's on the list (I'm waiting 4 it, too *g*), but not top-priority.