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EAGER fetching -- not working?!?

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troyaxn

Post subject: EAGER fetching -- not working?!?

Posted: Mon Oct 05, 2009 10:51 am

Newbie

Joined: Tue Nov 22, 2005 12:47 am
Posts: 6

i have a many-to-one class relationship that goes (other details snipped out):
note the FetchType being EAGER...

Code:

public class Customer{
   @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER)
   @JoinColumn(name="customer_id")
   @org.hibernate.annotations.IndexColumn(name="payPosition")
   @org.hibernate.annotations.Cascade(org.hibernate.annotations.CascadeType.DELETE_ORPHAN)
   @OrderBy("paymentDate")
   public List<CustomerPaymentHistory> getPaymentHistory() {
      return paymentHistory;
   }
}

however, when i try to iterate on the list,

Code:

      //retrieve data
      Customer cust = customerDao.findById(c1.getCustomerId());
      Assert.assertNotNull(cust);
      
      for(CustomerPaymentHistory cph : cust.getPaymentHistory()){
         System.out.println("\t" + cph );
      }

I get a no Session error which points to the for loop above considering that its not Lazily retrieved:

Quote:

performCustomerOperations(com.ifvi.rims.dao.test.CustomerDaoTest) Time elapsed: 0.976 sec <<< ERROR!
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:108)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:150)
at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:150)
at com.ifvi.rims.entities.Customer$$EnhancerByCGLIB$$bad860c2.getPaymentHistory(<generated>)
at com.ifvi.rims.dao.test.CustomerDaoTest.performCustomerOperations(CustomerDaoTest.java:130)

What did I miss in here?
Hope the info above is enough to state my point. Thanks!

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latha1119

Post subject: Re: EAGER fetching -- not working?!?

Posted: Tue Oct 06, 2009 12:14 pm

Regular

Joined: Mon Jan 05, 2009 6:42 pm
Posts: 99
Location: IL

Hi,
two things to be noted:-
1)In order to fix the issue you have one need to know what the customerDao.findById is actually doing? is it using a hibernate Load method or a get method? You might want to double check and use a get method on the object so that you get an initialized collection.

Code:

      //retrieve data
      Customer cust = customerDao.findById(c1.getCustomerId());
      Assert.assertNotNull(cust);
      
      for(CustomerPaymentHistory cph : cust.getPaymentHistory()){
         System.out.println("\t" + cph );
      }

also in your mapping fetch=FetchType.EAGER does not tell hibernate that you meant lazy="false" unless you have the lazy attribute set at the entity level.
So change the annotation or the mapping file for the attribute paymentHistory to have lazy="false" AND fetch=FetchType.EAGER. Then try both get and load methods appropriately.

2)For performance reasons its always better to use Lazy="true" and on the DAO method use the Fetch strategy to override the default behaviour. Something like:-
Criteria criteria = session.createCriteria(Customer.class);
customer = (Customer) criteria.setFetchMode("paymentHistory", FetchMode.<<appropriate mode>>).add(Restrictions.idEq(customerId))
.uniqueResult();

Hope this helps,
Srilatha.

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