Hi,
I am working on an application using seam 2.1.2 , deployed on Apache Tomcat 6.0.2 and mySql 5.0.67. I have 2 models called Branch and Supplier , with a one-to-many relationship between Branch and Supplier .
Code:
public class Branch {
............................
private Set<Supplier> suppliers = new HashSet<Supplier>(0);
............................
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "branch")
public Set<Supplier> getSuppliers() {
return this.suppliers;
}
public void setSuppliers(Set<Supplier> suppliers) {
this.suppliers = suppliers;
}
}
Code:
public class Supplier {
.............................
private Branch branch;
..............................
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "branch_id")
@NotNull
public Branch getBranch() {
return this.Branch;
}
public void setBranch(Branch branch) {
this.branch = branch;
}
}
The DAO's that I am using :-
To save supplier -
Code:
public void save(Supplier supplier) {
UserTransaction tx = Transaction.instance();
try {
if(!tx.isActiveOrMarkedRollback()){
tx.begin();
}
log.info("supplier id before persist : "+supplier.getId());
entityManager.persist(supplier);
log.info("supplier id after persist : "+supplier.getId());
entityManager.flush();
log.info("supplier id after flush : "+supplier.getId());
tx.commit();
tx.begin();
} catch (SystemException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NotSupportedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (RollbackException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (HeuristicMixedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (HeuristicRollbackException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
To update the Branch :-
Code:
public void update(PartPrice partPrice) {
log.info("Before merge : Size of supplier set : "+partPrice.getSuppliers().size());
entityManager.merge(partPrice);
log.info("Before flush , after merge : Size of supplier set : "+partPrice.getSuppliers().size());
entityManager.flush();
log.info("After flush : Size of supplier set : "+partPrice.getSuppliers().size());
}
Other information that could be of significance :-
1.Both the models have an overridden equals and hashcode method
2.The Dao's are Application Scoped
3.I am using DTO for capturing Data from the form , and then saving/deleting/updating it
My Problem : 1. A supplier is created and saved ,
for a Branch that has no suppliers as of now . This is of significance as , the problem is not encountered if the Branch has at least one supplier .
2. After the supplier is persisted (it is visible in the db) , I call a function to update the associated Branch . As you can see in my Dao for updating Branch , I am displaying the size of the supplier set before and after the update . The problem is that , as soon as the update happens , the supplier set for that Branch becomes empty . I cannot see the suppliers for that Branch on the webpage , or on my console .
3. If I keep adding more suppliers , the same behavior is observed . If , I do a refresh on the webpage , I can see the supplier list , and any supplier which is subsequently added . As I said before , this problem occurs only when there are no suppliers for a branch , and I add a new one .
So where am I going wrong ?
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