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https://issues.apache.org/jira/browse/HADOOP-7328?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13048698#comment-13048698
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[email protected] commented on HADOOP-7328:
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bq. On 2011-06-13 18:23:35, Matt Foley wrote:
bq. > Sorry if this is out of context, but is it really best to also return a
null here? Shouldn't it check for null result from getSerialization(), then
throw a (non-NPE) exception? Or do you prefer to do that check and throw at a
higher level of the code?
I thought about this while doing the review... my thinking was that our other
similar APIs do return null -eg CompressionCodecFactory.getCodecByName()
returns null if the specified codec isn't found. This API is also marked as
LimitedPrivate Evolving so it shouldn't be a problematic breaking change.
Maybe we should add a bit of javadoc saying "@returns null if no serializer is
known for the given class." ?
- Todd
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/884/#review817
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On 2011-06-11 22:10:17, Harsh J wrote:
bq.
bq. -----------------------------------------------------------
bq. This is an automatically generated e-mail. To reply, visit:
bq. https://reviews.apache.org/r/884/
bq. -----------------------------------------------------------
bq.
bq. (Updated 2011-06-11 22:10:17)
bq.
bq.
bq. Review request for hadoop-common and Todd Lipcon.
bq.
bq.
bq. Summary
bq. -------
bq.
bq. Since getSerialization() can possibly return a null, it is only right that
getSerializer() and getDeserializer() usage functions do the same, instead of
throwing up NPEs.
bq.
bq. Related issue to which this improvement is required:
https://issues.apache.org/jira/browse/MAPREDUCE-2584
bq.
bq.
bq. This addresses bug HADOOP-7328.
bq. http://issues.apache.org/jira/browse/HADOOP-7328
bq.
bq.
bq. Diffs
bq. -----
bq.
bq. src/java/org/apache/hadoop/io/serializer/SerializationFactory.java
dee314a
bq.
bq. Diff: https://reviews.apache.org/r/884/diff
bq.
bq.
bq. Testing
bq. -------
bq.
bq. Existing SequenceFile serialization factory tests pass. The change is
merely to make the functions return null instead of throwing an NPE within.
bq.
bq.
bq. Thanks,
bq.
bq. Harsh
bq.
bq.
> Give more information about a missing Serializer class
> ------------------------------------------------------
>
> Key: HADOOP-7328
> URL: https://issues.apache.org/jira/browse/HADOOP-7328
> Project: Hadoop Common
> Issue Type: Improvement
> Components: io
> Affects Versions: 0.20.2
> Reporter: Harsh J
> Assignee: Harsh J
> Labels: io, serialization
> Fix For: 0.23.0
>
> Attachments: HADOOP-7328.r1.diff, HADOOP-7328.r2.diff
>
>
> When you have a key/value class that's non Writable and you forget to attach
> io.serializers for the same, an NPE is thrown by the tasks with no
> information on why or what's missing and what led to it. I think a better
> exception can be thrown by SerializationFactory instead of an NPE when a
> class is not found accepted by any of the loaded ones.
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