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From "Bryan Pendleton (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-4062) Method override missing from DataValueFactory interface
Date Tue, 17 Feb 2009 01:57:59 GMT

     [ https://issues.apache.org/jira/browse/DERBY-4062?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Bryan Pendleton updated DERBY-4062:
-----------------------------------

    Attachment: addToInterface.diff

Attached patch adds the indicated method to the DataValueFactory interface.

The regular regression tests ran clean, except that I can't run the upgrade tests
right now due to svn.apache.org being down.

Can anyone think of a straightforward way to write a regression test for this?
Since the DataValueFactory API is an internal class, it's hard to expose
this problem from one of the typical JDBC JUnit tests. Can one of our
JUnit tests get an instance of the DataValueFactoryImpl in a simple manner?



> Method override missing from DataValueFactory interface
> -------------------------------------------------------
>
>                 Key: DERBY-4062
>                 URL: https://issues.apache.org/jira/browse/DERBY-4062
>             Project: Derby
>          Issue Type: Sub-task
>            Reporter: Bryan Pendleton
>            Assignee: Bryan Pendleton
>            Priority: Minor
>         Attachments: addToInterface.diff
>
>
> I believe the problem involves o.a.d.iapi.types.DataValueFactory.
> This interface defines dozens and dozens of overloads of the method
> getDataValue(), for lots of different combinations of datatypes.
> For most of the Java "boxed" types (Short, Long, Float, Double, etc.),
> DataValueFactory defines a pair of getDataValue() methods. For example,
> here are the method pair that the interface defines for Short:
>         /**
>          * Get a SQL smallint with the given value.  A null argument means get
>          * a SQL null value.  The second form uses the previous value (if non-null)
>          * to hold the return value.
>          *
>          */
>         NumberDataValue         getDataValue(Short value);
>         NumberDataValue         getDataValue(Short value, NumberDataValue previous)
>                                                         throws StandardException;
> HOWEVER, for the Integer type, DataValueFactory doesn't define both overloads,
> but only defines the 'previous'-style overload:
>         /**
>          * Get a SQL int with the given value.  A null argument means get
>          * a SQL null value.  Uses the previous value (if non-null)
>          * to hold the return value.
>          *
>          */
>         NumberDataValue         getDataValue(Integer value, NumberDataValue previous)
>                                                         throws StandardException;
> The actual implementation, in o.a.d.iapi.types.DataValueFactoryImpl, though,
> does implement both the Integer overloads. But this method is NOT present
> in the DataValueFactory interface:
>         NumberDataValue         getDataValue(Integer value);
>  Because this method is not present in the interface, code such as
>    row.setColumn(SYSXPLAIN_RESULTSET_NO_OPENS, dvf.getDataValue(no_opens));
> which the code anticipates will invoke the above method, instead calls the method
>    public UserDataValue getDataValue(Object value); 
> which has a very different behavior (instead of returning a SQLInteger, it returns a
UserType).
> This accidental invocation of the wrong implementation method was causing data corruption
> errors in regression tests for the DERBY-2487 patch, which uses the above setColumn call.
> Instead of inserting SQLInteger values into the system table, the code was inserting
> java.lang.Integer UserType values; since those values don't match the defined type of
> the column(s) in the system catalog, the table appeared to be corrupt.
> I believe that this problem never affects external Derby applications, but only internal
Derby code,
> as the DataValueFactory interface is an internal interface only. Still, since it appeared
to
> cause data corruption and invalid query results, it is potentially a quite serious problem.
> See this thread in the derby-dev archives for a bit more discussion:
> http://mail-archives.apache.org/mod_mbox/db-derby-dev/200902.mbox/%3C4997818E.3080007@amberpoint.com%3E

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