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https://issues.apache.org/jira/browse/AVRO-680?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14097281#comment-14097281
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Doug Cutting commented on AVRO-680:
-----------------------------------
> Do you see a use case where isMap should return false for non-string-map-key
> and isArray should return true?
In general, isArray must return true only for things that have an array schema
and isMap must return true only for things that have a map schema.
Non-string-key maps have array schemas so isArray should return true and isMap
should return false. Things that assume this are, e.g., GenericData#validate,
#toString, #instanceOf, and #getSchemaName. These must work correctly in order
to, e.g., correctly write unions that contains arrays and/or maps. This is the
same reason that, e.g., we don't use java.lang.String for enum symbols or
byte[] for fixed, but have distinct runtime types for these.
> Allow for non-string keys
> -------------------------
>
> Key: AVRO-680
> URL: https://issues.apache.org/jira/browse/AVRO-680
> Project: Avro
> Issue Type: Improvement
> Affects Versions: 1.7.6, 1.7.7
> Reporter: Jeremy Hanna
> Attachments: AVRO-680.patch, non_string_map_keys.zip,
> non_string_map_keys2.zip, non_string_map_keys3.zip,
> non_string_map_keys4.patch, non_string_map_keys5.patch,
> non_string_map_keys6.patch
>
>
> Based on an email thread back in April, Doug Cutting proposed a possible
> solution for having non-string keys:
> Stu Hood wrote:
> > I can understand the reasoning behind AVRO-9, but now I need to look for an
> > alternative to a 'map' that will allow me to store an association of bytes
> > keys to values.
> A map of Foo has the same binary format as an array of records, each
> with a string field and a Foo field. So an application can use an array
> schema similar to this to represent map-like structures with, e.g.,
> non-string keys.
> Perhaps we could establish standard properties that indicate that a
> given array of records should be represented in a map-like way if
> possible? E.g.,:
> {"type": "array", "isMap": true, "items": {"type":"record", ...}}
> Doug
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