ClassCastException on meaningful FK with non-standard Java to JDBC type mapping
-------------------------------------------------------------------------------
Key: CAY-1398
URL: https://issues.apache.org/jira/browse/CAY-1398
Project: Cayenne
Issue Type: Bug
Components: Core Library
Affects Versions: 3.0RC2
Reporter: Andrus Adamchik
Assignee: Andrus Adamchik
Priority: Minor
Fix For: Short term future
A rather odd case, that nevertheless we should handle:
TABLE1 (PK INT, FK CHAR(1))
TABLE2 (PK CHAR(1));
Class1 (fk : java.lang.Character, class2: Class2)
I.e. a relationship is mapped with FK also being a meaningful attribute, and
attribute type is not a standard JDBC mapping of CHAR(1) column. Depending on
the Class1 entity property iteration order, SelectTranslator builds a result
column either from an "fk" attribute definition (then it is correctly mapped as
java.lang.Character) or from "class2" relationship definition (which will end
up ignoring ObjAttribute and using java.lang.String). Later on when a property
is ready from the object, the later case results in ClassCastException (of
java.lang.String into java.lang.Character).
This is almost impossible to test. For the entity in my project switching
between JDK 1.5 and 1.6 makes all the difference (it fails under 1.5, but this
is really dependent on the relationship and attribute string key names).
A quick (and probably incorrect) fix is to make
SelectTranslator.appendQueryColumns(..) -> "visitRelationship" check for
existence of ObjAttribute for the join DbAttribute to ensure the right type is
selected. Although this may result in invalid to-one fault ObjectIds, as the
target entity may not have meaningful ID columns, and the ObjectId derived from
FK will not match ObjectId of the target object fetched directly.
A correct, but somewhat deep fix , would be to read the same ResultSet column
twice,and put 2 copies in the DataRow: one for meaningful attribute, and one
for generic FK. maybe all "attributeOverrides" in SelectTranslator should
follow this approach.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
