Re: Unexpected awakeFromInsertion() behaviour
Re: Unexpected awakeFromInsertion() behaviour
- Subject: Re: Unexpected awakeFromInsertion() behaviour
- From: Peter Vandoros <email@hidden>
- Date: Thu, 10 Jan 2008 10:37:46 +1100
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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