[FLINK-18599] Compile error when use windowAll and TumblingProcessingTimeWindows

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Bug
• Affects Version/s: 1.11.0
• Component/s: API / Scala
• Assignee: Unassigned
• Reporter: henvealf
• Created: 15/Jul/20 02:25
• Updated: 15/Jul/20 14:54
• Resolved: 15/Jul/20 14:54

Description

Code:

import org.apache.commons.lang3.StringUtils

import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment
import org.apache.flink.streaming.api.windowing.assigners.{TumblingProcessingTimeWindows}
import org.apache.flink.streaming.api.windowing.time.Time

import org.apache.flink.streaming.api.scala._
   
    val env = StreamExecutionEnvironment.getExecutionEnvironment
    val stream = env.fromElements("a", "b", "c")

    stream
      .filter((str: String) => StringUtils.isNotEmpty(str))
      .map( _ => 1)
      .windowAll(TumblingProcessingTimeWindows.of(Time.seconds(5)))
      .reduce((a1, a2) => a1 + a2)
      .print()

Compile failed:

error: type mismatch;
 found   : org.apache.flink.streaming.api.windowing.assigners.TumblingProcessingTimeWindows
 required: org.apache.flink.streaming.api.windowing.assigners.WindowAssigner[_ >: Int, ?]
Note: Object <: Any (and org.apache.flink.streaming.api.windowing.assigners.TumblingProcessingTimeWindows <: org.apache.flink.streaming.api.windowing.assigners.WindowAssigner[Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow]), but Java-defined class WindowAssigner is invariant in type T.
You may wish to investigate a wildcard type such as `_ <: Any`. (SLS 3.2.10)
      .windowAll(TumblingProcessingTimeWindows.of(Time.seconds(5)))
                                                 ^
one error found

 What went wrong?

 Scala version: 2.11

 Flink version: 1.11

 Thanks.