[jira] [Created] (FLINK-7629) Scala stream aggregations should support nested field expressions

[Shang Yuanchun (Jira)]

Gabor Gevay created FLINK-7629:
----------------------------------

             Summary: Scala stream aggregations should support nested field expressions
                 Key: FLINK-7629
                 URL: https://issues.apache.org/jira/browse/FLINK-7629
             Project: Flink
          Issue Type: Bug
          Components: Scala API, Streaming
            Reporter: Gabor Gevay
            Assignee: Gabor Gevay
            Priority: Minor
             Fix For: 1.4.0


In the Scala API, {{KeyedStream.maxBy}} and similar methods currently only work with a field name, and not with nested field expressions, such as "fieldA.fieldX". (This contradicts their documentation.)

The reason for this is that the string overload of {{KeyedStream.aggregate}} uses {{fieldNames2Indices}} and then calls the integer overload. Instead, it should create a {{SumAggregator}} or {{ComparableAggregator}} directly, as the integer overload does (and as the Java API does). The ctors of {{SumAggregator}} or {{ComparableAggregator}} will call {{FieldAccessorFactory.getAccessor}}, which will correctly handle a nested field expression.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)