Also here is a reason why I don't find ordering of relationships
particularly useful is that things like ordering are context dependent
("context" in a general sense)... The same mapping can be used by
different UI frontends with different ordering requirements.
Actually I even find callback mappings useless in my apps for that
same reason. And it is even worse with orderings, as lists of objects
may be reordered on the fly in the UI, initial ordering can be
affected by user preferences, etc.
So I feel like it looks good on a feature list, but will be barely
usable in practice. Anybody can give real life examples to the opposite?
Andrus
On Mar 3, 2010, at 3:51 PM, Andrus Adamchik wrote:
Are we going to track property changes of objects? E.g.:
// assume ordered on painting name
Painting p = ...
p.setName("A");
artist.addToPaintings(p);
p.setName("Z"); // should we reorder in this line?
I'd say no (although we can), and this probably means no to (1) and
(4). Although on commit we should probably detect that the ordering
property has changed, and reorder affected lists.
Andrus
On Mar 3, 2010, at 3:32 PM, Andrey Razumovsky (JIRA) wrote:
[ https://issues.apache.org/jira/browse/CAY-477?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Andrey Razumovsky updated CAY-477:
----------------------------------
Attachment: 477-proto.patch
Here's prototype of how I see the issue.
Orderings can be added to objRelationship, and they are relative to
*target* entity (e.g. to Painting for "Artist.paintingArray"
relationship). For relationships with orderings, resolving returns
ordered list.
Some things to be done:
(1) Collection methods, like add() addAll() should keep the order.
(2) Map and Set support
For (1) and (2) we'll need to introduce different underlying
implementation of PersistentObject*
(3) Modeler support
(4) Not sure of this --> set() method of collections and changing
the object in ordered collection should somehow keep order. This is
unseen truth for maps but will be a pain for lists. Do we need this??
Support for preordered relationships
------------------------------------
Key: CAY-477
URL: https://issues.apache.org/jira/browse/CAY-477
Project: Cayenne
Issue Type: Task
Components: Core Library, Modeler
Affects Versions: Undefined future
Reporter: Andrus Adamchik
Fix For: Undefined future
Attachments: 477-proto.patch
This is already supported on the client (PersistentObjectList).
Need to either add support for it to ToManyList or migrate
DataContext to use PersistentObjectList. In any event Modeler
support is needed.
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