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https://issues.apache.org/jira/browse/FLINK-7811?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Aljoscha Krettek closed FLINK-7811.
-----------------------------------
Resolution: Fixed
Release Note:
When using Scala 2.12 you might have to add explicit type annotations in places
where they were not required when using Scala 2.11. This is an excerpt from the
TransitiveClosureNaive.scala example in the Flink code base that shows the
changes that could be required.
Previous code:
{code}
val terminate = prevPaths
.coGroup(nextPaths)
.where(0).equalTo(0) {
(prev, next, out: Collector[(Long, Long)]) => {
val prevPaths = prev.toSet
for (n <- next)
if (!prevPaths.contains(n)) out.collect(n)
}
}
{code}
With Scala 2.12 you have to change it to:
{code}
val terminate = prevPaths
.coGroup(nextPaths)
.where(0).equalTo(0) {
(prev: Iterator[(Long, Long)], next: Iterator[(Long, Long)], out:
Collector[(Long, Long)]) => {
val prevPaths = prev.toSet
for (n <- next)
if (!prevPaths.contains(n)) out.collect(n)
}
}
{code}
The reason for this is that Scala 2.12 changes how lambdas are implemented.
They now use the lambda support using SAM interfaces introduced in Java 8. This
makes some method calls ambiguous because now both Scala-style lambdas and SAMs
are candidates for methods were it was previously clear which method would be
invoked.
Implemented on master in f8cbbb505c4ddb4955050689310447e2991a0484 and previous
commits.
> Add support for Scala 2.12
> --------------------------
>
> Key: FLINK-7811
> URL: https://issues.apache.org/jira/browse/FLINK-7811
> Project: Flink
> Issue Type: Sub-task
> Components: Scala API
> Reporter: Aljoscha Krettek
> Assignee: Aljoscha Krettek
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.7.0
>
>
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