Re: 2.0.4: child DataContext & localObject

Sun, 04 Nov 2007 04:07:21 -0800 

Thanks, Andrus.

Should I submit a bug report?  If so, can you tell me where I can do so?
Honestly, I'm a bit surprised that I seem to be the first person ever to want to do such a thing. Having a shared DataContext for reference data seems like fairly standard practice. Accessing that shared DataContext from another DataContext which happens to be a nested context, seems like something every app would need to do at some point... 

Regards,
Marc
----- Original Message ----- From: "Andrus Adamchik" <[EMAIL PROTECTED]> 
To: <[email protected]>
Sent: Sunday, November 04, 2007 11:39
Subject: Re: 2.0.4: child DataContext & localObject
Could be a bug then. Yes, 'localObject' should do the right thing for committed objects. 

Andrus


On Nov 4, 2007, at 12:23 PM, Marc A. Donis wrote:


Hi, thanks for the reply.

The ref object is committed.  In fact, it is read-only.

btw, I found a solution, which I do not like much:

@Override
public void setToOneTarget(String relationshipName, DataObject value, boolean setReverse) { if (value != null && value.getDataContext() != this.getDataContext()) { 
      DataContext dc = getDataContext();
      value = dc.refetchObject(value.getObjectId());
   }
   super.setToOneTarget(relationshipName, value, setReverse);
}
Clearly, this results in an unnecessary fetch to bring the reference object into the master object's DataContext. I'd still very much like to understand why simply doing "value = (DataObject) dc.localObject(value.getObjectId(), null);" causes the relationship to be reset to null by DataContext.onContextFlush(). Is this a bug? 

Regards,
Marc
----- Original Message ----- From: "Andrus Adamchik" <[EMAIL PROTECTED]> 
To: <[email protected]>
Sent: Sunday, November 04, 2007 09:43
Subject: Re: 2.0.4: child DataContext & localObject



Hi Marc,
is the target object ('ref') committed, or is it in some other state (new, modified, etc.)? 

Andrus

On Nov 3, 2007, at 12:36 PM, mad7777 wrote:

Just to follow up... I've tried doing:

@Override
public void setToOneTarget(String relationshipName, DataObject  value,
boolean setReverse) {
if (value != null && value.getDataContext() != this.getDataContext () && 
value.getDataContext() != this.getDataContext()) {
DataContext dc = getDataContext();
value = (DataObject) dc.localObject(value.getObjectId(), value);
value.setPersistenceState(PersistenceState.COMMITTED);
}
super.setToOneTarget(relationshipName, value, setReverse);
}

... but alas, the result is the same as below.
I admit I don't understand what is going on here. It seems that I can't use a shared DataContext in conjunction with a nested (i.e. child) DataContext? 
Is this a bug, or am I just going about this all wrong??

Marc



mad7777 wrote:


Hi,

I am seeing a strange interaction between child DataContexts and
localObject. If I set a to-one relationship from an object residing in a child context to another object which lives in that context's parent, I 
see:

org.apache.cayenne.CayenneRuntimeException: [v.2.0.4 October 12  2007]
Cannot
set object as destination of relationship abuseStatus because it is in a 
different DataContext

So I do:

 @Override
public void setToOneTarget(String relationshipName, DataObject value, 
boolean setReverse) {
if (value != null && value.getDataContext() != this.getDataContext() && 
value.getDataContext() != this.getDataContext()) {
   DataContext dc = getDataContext();
   value = (DataObject) dc.localObject(value.getObjectId(), null);
  }
  super.setToOneTarget(relationshipName, value, setReverse);
 }
in the child context object's class, which works fine (but seems like it 
should not be necessary?).

But what I really want is:

  DataContext refDataContext = DataContext.createDataContext();
  CayenneDataObject ref = ...// get reference from refDataContext
  DataContext userDataContext =
DataContext.createDataContext().createChildDataContext();
  CayenneDataObject obj =
userDataContext.createAndRegisterNewObject(MasterObject.class);
  obj.setRef(ref);
In other words, the obj's context (the child context) is not a child of 
the
referenced object's context.
In combination with the first bit of code, I now get:
org.apache.cayenne.validation.ValidationException: [v.2.0.4 October 12 
2007] Validation has failed.
Validation failure for MasterObject.ref: "ref"  is required.
because all the to-one relationship values set in this way are reset to 
null
during userDataContext.commitChanges()!

The stack looks like this:
MasterObject.setToOneTarget(UnAmourDataObject.java:11) *** value == null in this call org.apache.cayenne.access.ChildDiffLoader.arcCreated (ChildDiffLoader.java:120) org.apache.cayenne.access.ObjectDiff$ArcOperation.apply (ObjectDiff.java:428) 
org.apache.cayenne.graph.CompoundDiff.apply(CompoundDiff.java:97)
org.apache.cayenne.access.ObjectStoreGraphDiff.apply (ObjectStoreGraphDiff.java:136) org.apache.cayenne.access.DataContext.onContextFlush (DataContext.java:1188) 
org.apache.cayenne.access.DataContext.onSync(DataContext.java:1167)
org.apache.cayenne.access.DataContext.flushToParent (DataContext.java:1234) org.apache.cayenne.access.DataContext.commitChanges (DataContext.java:1138) 

Thoughts? Comments? Suggestions?

Thanks,
Marc





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