Re: Identity class and parent/children entity relationship

Wed, 08 Apr 2009 22:45:06 -0700 

Hi Fay -
Found my error here - my case now works on 1.2.1. I had a mapping error that caused the reentrant flush exception -- this is probably not the problem fixed by JIRA-1004. This is the story - I have a class with a OneToMany relationship to itself (parent has a collection of children of the same type). My mistake was to mark the "optional" attribute false. Obviously somebody is the granddaddy with no parent or you have a pathological cycle. So this works now - 

@Table (name="product_category")
public class ProductCategory
   implements java.io.Serializable
{
   @GeneratedValue(strategy=GenerationType.IDENTITY)
   @Id private long id;

   @OrderBy
   @OneToMany(mappedBy="parentCategory", fetch=FetchType.LAZY,
                         cascade={CascadeType.PERSIST,CascadeType.REMOVE})
   private List<ProductCategory> subCategories;

   @ManyToOne(fetch=FetchType.LAZY,cascade=CascadeType.PERSIST)
   private ProductCategory parentCategory;
}


On 4/7/2009 2:26 PM, Paul Copeland wrote:

I also have a hard requirement to work with 1.x.x OpenJPA (JPA 1.0) 
for a production delivery same as Nemanja.



So I am willing to jump through hoops for a work around even it means 
changing the identity type or doing lots of flushes or something else 
like that.  Just wondering what my options are.


I already tried doing flushes. Maybe I need to do a refresh too?

- Paul

On 4/7/2009 1:51 PM, Fay Wang wrote:

The fix is in JIRA-1004. I only checked in the fix to trunk, not 
1.2.x, though.


-Fay



----- Original Message ----
From: Paul Copeland <[email protected]>
To: [email protected]
Sent: Tuesday, April 7, 2009 12:34:05 PM
Subject: Re: Identity class and parent/children entity relationship

Is there a workaround for 1.2.1?


I'm also hitting the reentrant flush exception with 
GenerationType.IDENTITY



On 3/30/2009 10:26 AM, Nemanja Joksovic wrote:

 

Thanks Fay,


I tried it before and it's working fine. But in production 
environment I need to using stable OpenJPA 1.2.x version (JPA 1.0 
specification).


Regards,
Nemanja J.




The workaround is to use MappedById annotation (JPA 2.0 spec) in 
Openjpa trunk:


@Entity
public class Child implements Serializable {

    @EmbeddedId
    @Column(name = "id", unique = false, nullable = false)
    private ChildId childId;

    @MappedById("parent")
    @ManyToOne
    @JoinColumn(name = "parent_id", referencedColumnName = "id")
    private Parent parent;

...
}


@Embeddable
public class ChildId {
    public long id;
    public long parent;
   ...}


@Entity
public class Parent {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)

    @Column(name = "id", unique = true, insertable = false, 
updatable = false, nullable = false)

    private long id;
        @OneToMany(cascade = CascadeType.ALL, mappedBy = "parent")
    private List<Child> children = new ArrayList<Child>();
        private String name;
   ...}


For more detail, please see

org.apache.openjpa.persistence.enhance.identity.TestMappedById.testMappedById5 



-Fay

--- On Mon, 3/30/09, Nemanja Joksovic <[email protected]> wrote:


 
   

From: Nemanja Joksovic <[email protected]>
Subject: Re: Identity class and parent/children entity relationship
To: [email protected]
Date: Monday, March 30, 2009, 9:56 AM
Thank you very much.

Nemanja J.



The second problem is a known problem. I will open a JIRA
for it.


--- On Sun, 3/29/09, Nemanja Joksovic
<[email protected]> wrote:


        

From: Nemanja Joksovic <[email protected]>
Subject: Identity class and parent/children entity

             

relationship

        

To: [email protected]
Date: Sunday, March 29, 2009, 5:33 AM
Hi all,

I've been experiencing few problems with Identity

             

class

        

and Parent/Children entity relationship. I tried with

             

both

        

OpenJPA 1.2.1 and 2.0.0-SNAPSHOT. I have a very simple

             

test

        

case which can briefly explain problems:

@Entity
public class Parent implements Serializable {

    private long id;
    ....
    private List<Child> children = new
LinkedList<Child>();

    @Id
//  @GeneratedValue(strategy =

             

GenerationType.IDENTITY)

        

    @Column(name = "id", unique = true,
insertable = false, updatable = false, nullable =

             

false)

        

    public long getId() {
        return id;
    }

    public void setId(long id) {
       this.id = id;
    }

    ...

    @OneToMany(cascade = CascadeType.ALL, mappedBy =
"parent")
    public List<Child> getChildren() {
        return children;
    }

    public void addChild(Child child) {
        if (child == null) {
            throw new

             

IllegalArgumentException("Cannot

        

add a null Child");
        }
        this.getChildren().add(child);
    }

    public void setChildren(List<Child>

             

children) {

        

        this.children = children;
    }
}

@Entity
@IdClass(ChildId.class)
public class Child implements Serializable {

    private long id;
    ...
    private Parent parent;

    @Id
    @Column(name = "id", unique = false,

             

nullable

        

= false)
    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    ...

    @Id
    @ManyToOne
    @JoinColumn(name = "parent_id",
referencedColumnName = "id")
    public Parent getParent() {
        return parent;
    }

    public void setParent(Parent parent) {
        this.parent = parent;
    }
}

ChidId is generated with the Application Identity

             

Tool:

        

public class ChildId implements Serializable {
    ...
    public long id;
    public long parent;
    ...
}

1) Merge operation fail in any case with following
exception:

java.lang.NullPointerException
    at


             

net.company.persistence.Child.pcCopyKeyFieldsFromObjectId(Child.java)

        

    at


             

net.company.persistence.Child.pcNewInstance(Child.java)

        

    at


             

org.apache.openjpa.kernel.AttachStrategy.persist(AttachStrategy.java:93) 

        

    at


             

org.apache.openjpa.kernel.VersionAttachStrategy.attach(VersionAttachStrategy.java:100) 

        

    at


             

org.apache.openjpa.kernel.AttachManager.attach(AttachManager.java:241)

        

    at


             

org.apache.openjpa.kernel.AttachStrategy.attachCollection(AttachStrategy.java:333) 

        

    at


             

org.apache.openjpa.kernel.AttachStrategy.replaceList(AttachStrategy.java:359) 

        

    at


             

org.apache.openjpa.kernel.AttachStrategy.attachField(AttachStrategy.java:223) 

        

    at


             

org.apache.openjpa.kernel.VersionAttachStrategy.attach(VersionAttachStrategy.java:153) 

        

    at


             

org.apache.openjpa.kernel.AttachManager.attach(AttachManager.java:241)

        

    at


             

org.apache.openjpa.kernel.AttachManager.attach(AttachManager.java:101)

        

    at


             

org.apache.openjpa.kernel.BrokerImpl.attach(BrokerImpl.java:3212)

        

    ... 25 more


The problem is caused by the call
pc.NewInstance(AttachStrategy:93) with null state

             

manager

        

instance which is used in

             

pcCopyKeyFieldsFromObjectId(..):

        

             

pcsetParent((Parent)pcStateManager.getPCPrimaryKey(childid,

        

2 + pcInheritedFieldCount));

Also, for same problem exists JIRA Issue:
https://issues.apache.org/jira/browse/OPENJPA-218


2) Persist working fine, but it's fail in the case

             

when

        

Parent.id is Generated Value field with following

             

exception:

        

<openjpa-1.2.1-r752877:753278 fatal user error>
org.apache.openjpa.persistence.InvalidStateException:
Detected reentrant flush.  Make sure your flush-time
instance callback methods or event listeners do not

             

invoke

        

any operations that require the in-progress flush to
complete.
    at


             

org.apache.openjpa.kernel.BrokerImpl.flushSafe(BrokerImpl.java:1904)

        

    at


             

org.apache.openjpa.kernel.BrokerImpl.flush(BrokerImpl.java:1679)

        

    at


             

org.apache.openjpa.kernel.StateManagerImpl.assignObjectId(StateManagerImpl.java:524) 

        

    at


             

org.apache.openjpa.kernel.StateManagerImpl.assignObjectId(StateManagerImpl.java:506) 

        

    at


             

org.apache.openjpa.kernel.StateManagerImpl.fetchObjectId(StateManagerImpl.java:1434) 

        

    at


             

net.company.persistence.Parent.pcFetchObjectId(Parent.java)

        

    at


             

net.company.persistence.Child.pcCopyKeyFieldsToObjectId(Child.java)

        

Does exists some workaround for these problems ?

Regards,
Nemanja J.
--
View this message in context:


             

http://n2.nabble.com/Identity-class-and-parent-children-entity-relationship-tp2552430p2552430.html 

        

Sent from the OpenJPA Users mailing list archive at
Nabble.com.

             

    



--
View this message in context:

http://n2.nabble.com/Identity-class-and-parent-children-entity-relationship-tp2552430p2558373.html 


Sent from the OpenJPA Users mailing list archive at
Nabble.com.

         

    




 
    




     




  




























					Reply via email to