Hi Erik,
On Nov 18, 2005, at 2:27 AM, [EMAIL PROTECTED] wrote:
Thanks Craig.
When the JDO implementation generates the classes at runtime...
1 - Should the field-name attribute be used to generate the field
in the class?
No. The intent of the persistent interface is that the JDO
implementation creates an "anonymous" implementation class. There is
no requirement to even create a persistence-capable class; it's
perfectly fine to use dynamic Proxy as a strategy and to not even
define fields with names.
2 - There is no attribute that defines the binary name of the
generated class at
runtime. We may need a metadata attribute to allow specifying it,
and secondly,
we should define a default naming for the generated class if not
specified in
the metadata.
I have two proposals for a default:
- <interface-package>.Jdo<interface-classname>
- <interface-package>.<interface-classname>Impl
See above. There is no value in having a persistence-capable concrete
class visible to the user, as there is no user-visible behavior of
such a class. The only thing that a user can and should rely on is
that the persistent properties are available from the implementation
instance.
It seems that I wasn't clear in my reply below. Probably because
there are two different uses for persistent interfaces and properties.
The use referred to above is a persistent interface used in the
context of PersistenceManager.newInstance(interface.class). In this
case, the implementation generates some anonymous class that
implements the interface and can be made persistent via the standard
PersistenceManager API.
The use I thought you asking about below is where a user-defined
persistence capable class is declared to implement a persistent
interface, even without a persistent mapping for the persistent
interface. In this case, user-defined persistence capable classes
need a mapping between the persistent property name and the
persistent field name. This allows queries that take the persistent
interface as the candidate class and maps the queries to concrete
classes with fields.
I could add some text to the spec if you think it would help.
Regards,
Craig
Regards,
Erik Bengtson
Quoting Craig L Russell <[EMAIL PROTECTED]>:
Hi Erik,
On Nov 8, 2005, at 3:58 PM, [EMAIL PROTECTED] wrote:
Hi,
The element property in DTD misses the persistence-modifier
attribute.
On the same suject, I don't know the purpose of field-name in
property. Can
someone give me a light?
The purpose of field-name in property is to allow a query against a
property to be mapped to the appropriate field in each mapped
implementation class. So, if querying for a property called startDate
in Employee, it would be mapped to field beginDate in
PartTimeEmployee and to field beginningDate in FullTimeEmployee.
Craig
Regards,
Erik Bengtson
Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/
jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!
Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!
