Just to reiterate, these solutions where already mentioned:
* Compare data with snapshot as Bryan suggested (drawback -
relationship handling can be non-trivial)
* Use non-public method ObjectStore.getChanges with a custom
GraphChangeHandler to analyze the changes. The simplest and probably
best performing solution. Drawback - non-public API is subject to
change without notice.
I just thought of one more solution (haven't tried it yet)... It is
more consistent with the "modern" Cayenne API and is sort of a
combination of the two approaches above:
* Compare the state of the objects with a state of unmodified objects
in a peer context, using ClassDescriptor.visitProperties(..) method:
if(context.hasChanges()) {
ObjectContext peer = context.getParentDataDomain
().createDataContext();
PropertyVisitor visitor = ... // this class will analyze the changes,
// using peer context to obtain unmodified objects
// updated
Iterator it = context.modifiedObjects().iterator();
while(it.hasNext()) {
Persistent o = (Persistent) it.next();
ObjectId id = o.getObjectId();
ClassDescriptor descriptor = context.getEntityResolver
().getClassDescriptor(id.getEntityName());
descriptor.visitProperties(visitor);
}
// inserted and deleted can be analyzed without ClassDescriptor
}
Andrus
On Nov 7, 2006, at 11:51 AM, edward pedersson wrote:
Hi
I am trying to display the changes in the object graph as granular as
possible and I have come stuck in the objectStore. These methods
and fields
protected Map changes = new HashMap();
ObjectStoreGraphDiff getChanges() {
return new ObjectStoreGraphDiff(this);
}
Map getChangesByObjectId() {
return changes;
}
are all encapsulated quite heavily and I have no access to them
other than
creating a class in the org.apache.cayenne.access either as a
subclass of
ObjectStore or a stand alone class with an objectStore reference.
I can't see any other way to display any more useful information to
the user
other than the default DataObject.toString() which really only
tells the
user the object has changed but nothing more.
Has any body tried to do this before? Many thanks for your help.
e--
---------- Forwarded message ----------
From: edward pedersson <[EMAIL PROTECTED]>
Date: 09-Oct-2006 11:11
Subject: reverting changes and displaying commited changes
To: Cayenne Users <[email protected]>
Hi
I have built an application using Cayenne and Tapestry running under
Tomcat on a Linux server. I am using the latest released versions of
all of the above.
I would like to be able to display to the user the current changes in
the DataContext and allow the user to revert individual changes. I
would also like them to be able to see what values the object had
before the change.
I have read the documentation and thought about having nested contexts
but at times I would have to deal with 50+ context so it seems a bit
unmanageable.
Any thought would be most helpful.
Thanks in advance.
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