Getting a ClassCastException in hibernate

Question

I'm writing some code in hibernate where I'm required to update some other table (hall_calendar) before a row is inserted in my table (hall_block_calendar). I have status F, E, M from which only those dates submitted by the form having "F" are to be marked "N". My mapping file for pojo class Hall_calendar.java contains composite key for hall_code and calendar_date and hallbookingcompid in the pojo class.

My query is working fine. However, the for loop throws an exception. I would appreciate any inputs on this.

        public boolean addHallCalendarBlock(Hall_block_calendar hbc, Hall_calendar hc)
{
   //boolean result;
   Session session=HibernateUtil.getSessionFactory().openSession();   
   Transaction tx=null;
   try
    {
       tx=session.beginTransaction();

       Query q=session.createQuery("from Hall_calendar h where h.hallbookingcompid.calendar_date between'"+hbc.getHall_block_from_date()+"' and '"+hbc.getHall_block_to_date()+"' and hall_availability='F'");

       System.out.println("query working: "+q.list());

       if(!q.list().isEmpty())
       {   
           Hall_calendar upd_obj = new Hall_calendar();
           for(Iterator it=q.iterate();it.hasNext();)
           {   


             Object[] row = (Object[]) it.next();
             System.out.println("row[0]: "+(String)row[0]);
             upd_obj= (Hall_calendar) session.load(Hall_calendar.class, (String)row[0]);

             upd_obj.setHall_availability("N"); 
             session.save(upd_obj); 
           }

           session.save(hbc);
           tx.commit();  
       }   
    }
   catch(Exception e)
   {
       tx.rollback();
       e.printStackTrace();
       return false;
   }
   finally
   {
       session.close();
   }
   return true;
}


query working: [com.cmc.sibs.vo.Hall_calendar@7e9bed, com.cmc.sibs.vo.Hall_calendar@4d2125, com.cmc.sibs.vo.Hall_calendar@1bb41d7, com.cmc.sibs.vo.Hall_calendar@df9252]
java.lang.ClassCastException: com.cmc.sibs.vo.Hall_calendar
    at com.cmc.sibs.dao.SibsDao.addHallCalendarBlock(SibsDao.java:21861)
    at com.cmc.sibs.delegates.SibsDelegate.addHallCalendarBlock(SibsDelegate.java:2982)
    at com.cmc.sibs.servlets.AddHallBlocking.doPost(AddHallBlocking.java:86)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
    at java.lang.Thread.run(Unknown Source)
boolean in servlet: false

I do hope that is not production code. (Imperatively demarcating transactions in every DAO operation, "logging" with e.printStackTrace, returning a boolean to indicate an error condition rather than throwing an exception, ...) — meriton
– meriton, Commented Sep 16, 2012 at 17:49

Tobb · Accepted Answer · 2012-09-16 17:43:44Z

3

First off, you're violating every Java code standard. You are basically writing c++ code with Java. Secondly, I do not get why you iterate the way you do. When you do a query.list(), on a query without a select clause, you will get back full objects. Why not do:

final List<Hall_calendar> res = (List<Hall_calendar>) q.list();
for (final Hall_calendar hall_calendar : res) {
    hall_calendar.setHall_availability("N");
    //no need to explicitly save these..
}
session.save(hbc);

edited Sep 16, 2012 at 17:43

answered Sep 16, 2012 at 17:27

Tobb

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commit · Accepted Answer · 2012-09-16 18:41:37Z

0

You use "Query" interface and it has not iterator() method. Take one list store query result to that list using list() method and u can make a for loop in following way.

for(class_name object : list_name)
{
//Performed action using object
}

answered Sep 16, 2012 at 18:41

commit

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