[Hibernate-issues] [Hibernate-JIRA] Created: (HHH-1621) subclass mapping by discriminator - should instantiate parent for unmapped discriminator values

[Martin S. (JIRA) <no...@at...>]

subclass mapping by discriminator - should instantiate parent for unmapped discriminator values
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         Key: HHH-1621
         URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1621
     Project: Hibernate3
        Type: Improvement

  Components: core  
 Environment: 3.1.2
Sybase ASE 12.5.3
    Reporter: Martin Schulz


Scenario:  The parent class A has a discriminator field and some but all possible scriminator values are mapped to subclasses.

Current behavior:
1) Default:
The following exception is thrown
org.hibernate.WrongClassException: Object with id: 10000 was not of the specified subclass: A (Discriminator: D)
	at org.hibernate.loader.Loader.getInstanceClass(Loader.java:1445)
[ the error itself is also quite misleading, as the row is exactly of / for the specified class A. But there simply was no
  subclass found ].
2) discriminator with force="true"
The parent class is never instantiated, only the mapped subclasses are instantiated.

Proposed behavior:
The parent class should be instantiated for those rows with unmapped discriminator values.

Characteristics of proposed behavior:
- all rows in resultset would lead to instantiated class in the inheritence tree,
- the behavior would be in line with how joined-subclass behaves
- no caveat documentation required

Implementation:
(Easy)
in Loader.java, lines 1443ff, do not throw WrongClassException, but instead 
return persister.getEntityName();
(Alternate)
change persister.getSubclassForDiscriminatorValue() implementations correspondingly.

Thx for your consideration / vote.



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