Re: [Figleaf-developer] Questions regarding ObjectManager

[Greg S. <ste...@on...>]

sam...@ma... wrote:

>Firstly, is this better off being named something like PersistenceLayer?
>
>  
>
Maybe. But because I had the "Informative introspect(Object obj);" 
method in there that brought it out of being purely for persistence. 
Also I figured there's probably going to be non-persistence stuff we'll 
need to put somewhere (logins, security?).

>Secondly, there seems to be some overlapping methods, for example (this from my
>TransientObjectManager):
>
>public Informative newInstance(Class clazz) {
>  return informativeFactory.createInformative(clazz.newInstance());
>}
>
>public Informative introspect(Object obj) {
>  return factory.createInformative(obj);
>}
>
>Are both needed? I'm keen not to put in a requirement for methods to be
>implemented that we might not even end up using.
>  
>

The introspect method was because I thought about the case if a POJO 
creates an object (using new) and returns it from a method call. Then 
the UI will need to get the ObjectManager to proxy it and turn it into 
an Informative so it can be displayed. Some thought still needs to be 
given to when such an object should be persisted: as soon as its called, 
force the user to press a save button, or never...? Then there's the 
issue of what if that happens in a transaction. I'm not sure it's 
practical to expect all objects to know nothing about ObjectManager and 
just use new. If we require them to always use the ObjectManager when 
creating a new instance, then the introspect method probably isn't needed.

>As for the method:
>
>Informative getObject(Class clazz, Serializable id);
>
>Do we need this? Surely this should be handled by whatever query mechanism we use.
>
>sam
>
>
>  
>
It'll probably be needed by lazy initializing proxies and collections. 
They will only know the id and which class they represent. When they 
need to load their data they can call this method and get a fully 
populated object back. Perhaps it doesn't belong in the ObjectManager 
"layer" but rather in a persistence and proxy layer.

Greg