Hi Florent!
Florent Guillaume wrote:
On 27 Dec 2005, at 10:51, yuppie wrote:
Florent Guillaume wrote:
Also I'd like to change things like:
node = property(_exportNode, _importNode)
into:
def __exportNode(self):
return self._exportNode()
def __importNode(self, *args)
self._importNode(*args)
node = property(__exportNode, __importNode)
To allow proper subclass overriding and avoid the dead chicken of
having to redefine the node property each time.
Done.
But in my (complex) setup it revealed an unintended side effect. There
are actually 3 useful methods when doing export (also valid for import):
- export as simple node for its parent file (just the <object name="foo"
meta_type="bar"> part),
- export as full node tree,
- export as XML body using the "full node" code.
Correct.
Before, the fact that you defined or not
node = property(_exportNode, _importNode)
made the export "do the right thing", as
- _extractObjects calls exporter.node, thus calls the last node
property defined, whereas
- _exportBody calls self._exportNode(), thus inherits
This is *very* implicit and magic, and would benefit from some
refactoring...
Well. That's the way property() works. Your change adds magic because it
makes property() inherit its methods.
The current status of the code is that exports of more that one level
are currently not correct.
It seems there's no unit test for it...
There are no real unit tests for it, but there are many unit tests for
adapters using those base classes. These are at the same time
integration tests for the base classes in GenericSetup.utils. Some
CMFCore tests are failing after your change.
I'll fix this in a few days unless someone is interested to do it before
then.
I don't think it's a good idea to make obviously incomplete checkins to
the trunk. Why didn't you create a branch?
I propose to have _exportSimpleNode for the basic version, _exportNode
for the full version, and have _extractObjects call _exportSimpleNode
and _exportBody call _exportNode. The node property would refer to the
full version.
_extractObjects sometimes needs the simple node (if the sub-object has
its own XML file) and sometimes the full node (if the sub-object
settings should be part of the parent's XML file).
Only the sub-object adapter knows which node _extractObjects needs. The
node property should always return the correct node. _extractObjects
should not call a private method of the sub-object adapter.
_exportBody always needs the full node, but it doesn't need to use a
public method.
Moreover, I propose to *deprecate* the .node and .body properties, I
don't see how they help readability and having properties do complex
work is really not intuitive to me. They're doing more harm than
anything else (anytime I read the code I have to scratch my head and
remember that it's not just an attribute assignment).
The setup handlers don't care about how the body or the node is stored
inside the object. If this is internally a complex operation or a simple
attribute assignment doesn't matter. From the setup handler point of
view this is a simple read or write operation.
For read/write operations properties are intuitive to me. But if I'm the
only one who thinks that way it's not too late to change INode and
IBody. We are still in the alpha phase.
Cheers,
Yuppie
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