Mr. Pierre Frisch wrote:
--
Pierre Frisch
email@hidden
On Jan 10, 2008, at 18:37, Chuck Hill wrote:
On Jan 10, 2008, at 12:31 PM, Mr. Pierre
Frisch wrote:
I am not entirely sure of what the behavior
should be but after the save the object is in the DB so this not a
newly inserted object anymore.
That is a good point. I'd guess if this is not a simple bug, that
someone was looking as insert as the opposite of delete when
reverting. But that is not quite true.
This is exactly how the code work by re-inserting the deleted object
and this is why the awakeFromInsertion() get called.
We do a deleteObject() and a revert()
logically we should call awakeFromFetch() as this would have reverted
the object to its fetched state (last snapshot), awakeFromInsertion()
just does not appears to make sense.
At first it made sense to me. In database terms, doing an insert to
revert a delete makes sense. But you are right, this is not how EOF
should revert.
If awakeFromFetch() changes any values after reverting, do these get
seen by the EC and saved to the DB? That is something to check.
As per the documentation revert() restore the last snapshot value in
the EO. It does not touch any other field i.e. the objects are not
recreated merely updated. What is the right behavior: do nothing of
call awakeFromFetch()? One way or another there may be unintended
repercussions. But any value initialized in awakeFromFetch( will be
save at the next DB save.
In my opinion, neither awakeFromFetch() or awakeFromInsert() should be
called because as a developer, you expect the object graph to be in the
same state as it was when the last saveChanges() was called. I think
you should mimic the behaviour for how reverting a changed object is
done.
In any case, the object should be changed in any way. If for some
reason, you change requirement for either awakeFromFetch() or
awakeFromInsertion() being called, then at the very least, any changes
to the object during this process should not be lost.
Chuck
On Jan 10, 2008, at 11:35, Chuck Hill
wrote:
I will let Peter file the report. But
while you are waiting...
What do you think is the correct behavior here? Should it not call
awakeFromInsertion again? Should it call it and undo any changes?
Should it call it and detect that the object has been updated?
Calling revert() should, I think, return the contents of the EC to the
last state where there were no changes (after the previous save if it
has been saved, or will all local changes undone). Calling
awakeFromInsertion() does not seem compatible with that.
Chuck
On Jan 10, 2008, at 11:30 AM, Mr. Pierre Frisch wrote:
Bug report please this needs to be
fixed.
Pierre
--
Pierre Frisch
email@hidden
On Jan 10, 2008, at 11:04, Chuck Hill wrote:
That looks like a bug, the EC should
either not be calling awakeFromInsertion() or should be seeing the
notifications from the change in value. It makes sense to me for it to
call awakeFromInsertion() *BUT* this results in an object state
different from what was there before the changes being reverted. That
seems to be a very wrong result.
You will often see the method written as:
// in Order.java
public void awakeFromInsertion(EOEditingContext ec) {
super.awakeFromInsertion(ec);
if (statusMessage() == null) {
setStatusMessage("incomplete");
}
}
I don't do that myself (I probably should!), but I expect this is done
to handle the situation you are seeing.
Chuck
On Jan 9, 2008, at 3:37 PM, Peter Vandoros wrote:
Hi Chuck,
Chuck Hill wrote:
Hi Peter,
On Jan 9, 2008, at 2:49 PM, Peter Vandoros wrote:
Chuck Hill wrote:
On Jan 8, 2008, at 9:23 PM, Peter Vandoros wrote:
I came across an interesting behaviour today with awakeFromInsertion()
that i did not expect and I hope someone could shed some light.
What happens is that awakeFromInsertion() is not only called when the
EO is "created" but also when reverting the editing context after
having deleted an EO (which hasn't yet been saved). That is, if you
delete an EO and revert() instead of saveChanges(), that EO's
awakeFromInsertion() method is called again.
The documentation states:
"Overridden by subclasses to perform additional initialization on the
receiver upon its being inserted into ec. This is commonly used to
assign default values or record the time of insertion. ...."
I originally took this to mean that it is only called when the EO is
_created_. Technically speaking, the documentation states that it is
called when the EO is _inserted_ into the editing context which does
not necessarily mean when the EO is _created_.
Does this mean that I need to go through all my EO's that use this
method for some initialisation and take this scenario into account or
is this a bug with WO?
I am using WO 5.2.4.
Is this what you are talking about?
com.webobjects.eocontrol.EOEditingContext ec = newEditingContext();
ec.lock();
Order o = new Order();
ec.insertObject(o);
ec.deleteObject(o);
ec.revert();
ec.unlock();
I log a stack trace from Order.awakeFromInsertion. I do not get a call
to awakeFromInsertion when the ec is reverted in WO 5.3.3.
Log out a stack trace from awakeFromInsertion and see what it says for
the second call:
public void awakeFromInsertion(EOEditingContext ec)
{
NSLog.out.appendln(new RuntimeException("backtrace"));
super.awakeFromInsertion(ec);
. . .
I'd be interested to see it.
That is not exactly what i am talking about.
The code below demonstrates what i am talking about.
EOEditingContext ec = new EOEditingContext();
ec.lock();
try {
Order order = (Order) EOUtilities.createAndInsertInstance( ec, "Order"
);
// set order properties so it can be saved successfully
ec.saveChanges();
ec.deleteObject( order);
NSLog.out.appendln("should see awakeFromInsertion call now...");
ec.revert();
NSLog.out.appendln("did you see the awakeFromInsertion call?");
}
catch (Exception e) {
System.err.println("Error with test");
e.printStackTrace();
}
finally {
ec.unlock();
}
The stack trace (the interesting part) that i get when this happens is:
java.lang.RuntimeException: backtrace
at com.etechgroup.test.eo.Order.awakeFromInsertion(Order.java:44)
at
com.webobjects.eocontrol.EOEditingContext.insertObjectWithGlobalID(EOEditingContext.java:2851)
at
com.webobjects.eocontrol.EOEditingContext.insertObject(EOEditingContext.java:2871)
at
com.webobjects.eocontrol.EOEditingContext.revert(EOEditingContext.java:4570)
It looks as though the editing context re-inserts a deleted EO if that
EO is not newly created and you revert.
Of course it does! deleteObject makes the object not exist. Reverting
that makes it exist again. So it is newly created and get awoken
again. Revert is more like undo than "forget what I just changed".
ec.deleteObject(order);
ec.saveChanges();
ec.undo();
ec.saveChanges();
I am not sure of the exact calls, but it is possible to reverse changes
committed to the database. Or it was at one time, I have seen this
happen due to a bug processing delete rules. Much fun debugging that
one.
I can imagine :-)
I'm glad i cleared this up and gave other people on this list a heads
up about this behaviour. At least now I know about this and have worked
around it by creating a new method in my generic record super class
awakeFromCreate() which is called by awakeFromInsertion() only if the
EO is newly created. This way, it does what i thought
awakeFromInsertion() does and what i was using it for.
On a side note, i also noticed that if the default values that are set
in awakeFromInsertion() differ from the committed value, EOF does not
pick up that change leaving that EO/EditingContext in an invalid state.
This is actually what bit me yesterday and lead me to investigate this
behaviour.
This one _may_ be a bug. I can report it if you think it is a bug.
For example:
// in Order.java
public void awakeFromInsertion(EOEditingContext ec) {
super.awakeFromInsertion(ec);
setStatusMessage("incomplete");
}
// in SomeTestFile.java
EOEditingContext ec = new EOEditingContext();
ec.lock();
try {
Order order = (Order) EOUtilities.createAndInsertInstance( ec, "Order"
);
order.setStatusMessage("complete");
ec.saveChanges();
ec.deleteObject( order );
System.out.println("should see awakeFromInsertion call now...");
ec.revert();
System.out.println("did you see the awakeFromInsertion call?");
// the stateMessage should be 'complete' but you will see that it is
'incomplete'
NSLog.out.appendln("order.statusMessage should be 'complete', but it
is: " + order.statusMessage());
// the editing context also does not show any changes
NSLog.out.appendln("ec.hasChanges: " + ec.hasChanges());
NSLog.out.appendln("ec.insertedObjects: " +
ec.insertedObjects().count());
NSLog.out.appendln("ec.updatedObjects: " +
ec.updatedObjects().count());
NSLog.out.appendln("ec.deletedObjects: " +
ec.deletedObjects().count());
}
catch (Exception e) {
System.err.println("Error with test");
e.printStackTrace();
}
finally {
ec.unlock();
}
As always Chuck, your help is much appreciated.
Thanks
--
Peter Vandoros
Software Engineer
Etech Group Pty Ltd
Level 3/21 Victoria St
Melbourne VIC 3000
Australia
Ph: +61 3 9639 9677
Fax: +61 3 9639 9577
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Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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Peter Vandoros
Software Engineer
Etech Group Pty Ltd
Level 3/21 Victoria St
Melbourne VIC 3000
Australia
Ph: +61 3 9639 9677
Fax: +61 3 9639 9577
----------------------------------
IMPORTANT: This e-mail message and any attachments are confidential and
may be privileged. If received in error, please reply to this message
and destroy all copies and any attachments. You should check this
message and any attachments for viruses or defects. Our liability is
limited to resupplying any affected message or attachments. For more
information about Etech Group, please visit us at
http://www.etechgroup.com.au. |