Hi Blaise,
First off, welcome back, and best wishes on your
"blessed event".
There's no doubt that the 2.1 spec allows, even encourages,
deleted objects be reused in the graph. I just couldn't help but wonder
why user would want to do such a thing. Pooling was just
a guess, because I can't think of anything else.
The scenario you mention could also be handled with a
detach. The only difference is that with the delete, all non-readonly
properties are reset. If you're just moving something, that seems like an
odd and confusing thing to do. So why call delete? If it's really
desirable to reset the non-readonly properties too, then the user can of course
do so himself. But do you have a use-case for this?
My thinking is really to replace the statement you quote
with something along that lines that it is a "user error" to reuse a deleted
object, resulting in "undefined behavior". This leaves implementations
free to provide a backwards compatible option. That maybe helps, but it
doesn't change the fact that we are talking about breaking compatibility
here. On the other hand,
1) I believe the functionality is nonsencical, and
very rarely used (though I have no evidence of this)
2) We can offer users the ability to achieve the same
result using other means.
Best Regards,
Ron
Hi Ron,
Based on the following statement, I never interpreted
this as a means of implementing a pool of DataObjects, rather I took it to mean
that I can put this deleted object back in the graph and it is now a modified
rather than a deleted object (it maintains its object identity). In other
words a deleted object is not a dead object.
"A deleted DataObject can be used again, have its values
set, and again be added into the data graph."
If this statement was removed, does that mean we need to
guard against deleted objects being put back in the graph? Possibly
throwing an exception, this would be a backwards compatibility
issue.
-Blaise
Barack, Ron wrote:
1BC7B594EE497146B0CFF2F493B6823406C6D07382@DEWDFECCR02.wdf.sap.corp" type="cite">
RAISED BY: Ron
ChangeSummary is defined as a diff between
the state of the graph when beginLogging was called, and the state when
endLogging was called. The API used to modify the graph does not enter
into the the definition.
Users that call DataObject.delete
expect for the object to be represented in the change summary as a
deleted object. Usually, that is what they get. But the description of
the delete method seems to suggest that delete is rather more intended
for implementing a pool of DataObjects, that are freed and later re-used
in the graph. If delete is used in this way, it is possible that the
"deleted" object appears as a modified object in the change summary.
PROPOSAL: The utility of implementing object pools is
questionable to say the least. It seems more reasonable to say that the
delete method is intended to indicate the object should be deleted...as
opposed to detach, which is a step towards moving the object.
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