[jira] [Assigned] (AVRO-873) SpecificDatumReader should allow users to specify the ClassLoader used.

["Doug Cutting (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AVRO-873?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Doug Cutting reassigned AVRO-873:
---------------------------------

    Assignee: Michael Armbrust

Looks like a useful addition.

Perhaps instead of adding a new field to SpecificDatumReader we can add a new method to SpecificData, since the base GenericData already has a field containing the desired value:

{code}
public SpecificData getSpecificData() { return (SpecificData)getData(); }
{code}

Then this can be used in SpecificDatumReader, as getSpecificData().getClass(...).

Also, I'd prefer if the classLoader field were defined nearer the top of the class, since it's used by both a constructor and the getClass() implementation.  I'd place it just before the constructors.


> SpecificDatumReader should allow users to specify the ClassLoader used.
> -----------------------------------------------------------------------
>
>                 Key: AVRO-873
>                 URL: https://issues.apache.org/jira/browse/AVRO-873
>             Project: Avro
>          Issue Type: Improvement
>          Components: java
>            Reporter: Michael Armbrust
>            Assignee: Michael Armbrust
>         Attachments: specificDataClassLoader.patch
>
>
> Right now SpecificData resolves classes for SpecificRecords by calling Class.forName(), which uses the ClassLoader used to load the SpecificData class. I believe this makes it impossible to deserialize into SpecificRecords that are loaded using a different ClassLoader.
> One relatively simple way to fix this limitations involves:
> * Adding a constructor to SpecificData that allows the user to specify a ClassLoader.
> * Changing the current protected constructor of SpecificDatumReader that takes a SpecificData to be public instead of protected.
> * Changing SpecificDatumReader to actually use the SpecificData that is passed into the constructor.

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