[JDO-630] Support specification of exact class in SingleFieldIdentity

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: JDO 3 (3.0)
• Component/s: specification, tck
• Assignee: Unassigned
• Reporter: Andy Jefferson
• Created: 15/Apr/09 07:20
• Updated: 14/Jun/10 11:02
• Resolved: 26/Jan/10 18:24

Description

When calling PersistenceManager.getObjectById() with a SingleFieldIdentity, there seems to be no way of avoiding the following
(if the implementation decides to do so):
"It is an implementation decision whether to access the data store, if required to determine the exact class. This will be the case of inheritance, where multiple <code>PersistenceCapable</code> classes share the same ObjectId class."

Now when I know for sure that the targetClassName of the given SingleFieldIdentity already denotes the correct class for the given id, how can I avoid that additional roundtrip to the database for finding the exact class?

It would be useful to have a way of specifying a SingleFieldIdentity to be for the exact class specified. This could be done by addition of methods
void setExact(boolean flag);
boolean getExact();
to SingleFieldIdentity