[refacto] Drop Flink 1.18 support to reunify most of Flink 1 & 2 code

.github/workflows/ci.yml

@@ -14,22 +14,18 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        java: [11]
+        java: [11, 17]
         scala: [2.13.16, 3.3.6]
-        flink: [1.18.1, 1.19.1]
+        flink: [1.19.3, 1.20.2]
         sbt-module: ['flink-1-api', 'scala-api-common']
         include:
-          - scala: 3.3.6
-            java: 17
-            flink: 1.20.0
-            sbt-module: 'flink-1-api'
-          - scala: 3.3.6
+          - scala: 2.13.16
             java: 17
-            flink: 1.20.0
-            sbt-module: 'scala-api-common'
+            flink: 2.0.0
+            sbt-module: 'flink-2-api'
           - scala: 3.3.6
-            java: 17
-            flink: 2.0.0          
+            java: 21
+            flink: 2.0.0
             sbt-module: 'flink-2-api'
     env:
       JAVA_OPTIONS: '--add-opens java.base/java.lang=ALL-UNNAMED'
@@ -47,7 +43,7 @@ jobs:
         run: JAVA_OPTS=$JAVA_OPTIONS sbt "++ ${{ matrix.scala }} docs/mdoc"
       - name: Run tests on examples
         # always running on Scala 3.x version by default
-        if: ${{ !startsWith(matrix.flink, '1.18') && !startsWith(matrix.flink, '2.') }}
+        if: ${{ !startsWith(matrix.flink, '2.') }}
         run: JAVA_OPTS=$JAVA_OPTIONS sbt -DflinkVersion1=${{ matrix.flink }} "project examples; test"
       - name: Run tests on Flink API         
-        run: JAVA_OPTS=$JAVA_OPTIONS sbt -DflinkVersion1=${{ matrix.flink }} -DflinkVersion2=${{ matrix.flink }} "++ ${{ matrix.scala }}; project ${{ matrix.sbt-module }}; test"
+        run: JAVA_OPTS=$JAVA_OPTIONS sbt -DflinkVersion1=${{ matrix.flink }} -DflinkVersion2=${{ matrix.flink }} "++ ${{ matrix.scala }}; project ${{ matrix.sbt-module }}; test"

build.sbt

@@ -6,7 +6,7 @@ Global / excludeLintKeys      := Set(git.useGitDescribe, crossScalaVersions)
 
 lazy val rootScalaVersion = "3.3.6"
 lazy val crossVersions    = Seq("2.13.16", rootScalaVersion)
-lazy val flinkVersion1    = System.getProperty("flinkVersion1", "1.20.1")
+lazy val flinkVersion1    = System.getProperty("flinkVersion1", "1.20.2")
 lazy val flinkVersion2    = System.getProperty("flinkVersion2", "2.0.0")
 
 lazy val root = (project in file("."))
@@ -114,9 +114,12 @@ lazy val `scala-api-common` = (project in file("modules/flink-common-api"))
     scalaVersion       := rootScalaVersion,
     crossScalaVersions := crossVersions,
     libraryDependencies ++= Seq(
-      "org.apache.flink" % "flink-streaming-java" % flinkVersion1 % Provided,
-      "org.scalatest"   %% "scalatest"            % "3.2.19"      % Test,
-      "ch.qos.logback"   % "logback-classic"      % "1.5.17"      % Test
+      "org.apache.flink"  % "flink-streaming-java" % flinkVersion1 % Provided,
+      "org.apache.flink"  % "flink-test-utils"     % flinkVersion1 % Test,
+      ("org.apache.flink" % "flink-streaming-java" % flinkVersion1 % Test).classifier("tests"),
+      "org.typelevel"    %% "cats-core"            % "2.13.0"      % Test,
+      "org.scalatest"    %% "scalatest"            % "3.2.19"      % Test,
+      "ch.qos.logback"    % "logback-classic"      % "1.5.17"      % Test
     )
   )
 
@@ -192,6 +195,7 @@ lazy val `examples` = (project in file("modules/examples"))
       "ch.qos.logback"   % "logback-classic"            % "1.4.14"      % Provided,
       "org.apache.flink" % "flink-test-utils"           % flinkVersion1 % Test,
       "org.apache.flink" % "flink-streaming-java"       % flinkVersion1 % Test classifier "tests",
+      "org.typelevel"   %% "cats-core"                  % "2.13.0"      % Test,
       "org.scalatest"   %% "scalatest"                  % "3.2.15"      % Test
     ),
     Compile / run := Defaults

modules/examples/src/test/scala/org/example/CustomTriggerTests.scala

@@ -8,10 +8,8 @@ import org.scalatest.time.Seconds
 import org.scalatest.time.Span
 import org.scalatest.time.Millis
 import org.scalatest.Inspectors
-
 import org.apache.flinkx.api.*
 import org.apache.flinkx.api.serializers.*
-
 import org.apache.flink.streaming.util.KeyedOneInputStreamOperatorTestHarness
 import org.apache.flink.streaming.api.operators.KeyedProcessOperator
 import org.apache.flink.streaming.api.functions.KeyedProcessFunction
@@ -26,17 +24,17 @@ import org.apache.flink.streaming.runtime.streamrecord.StreamRecord
 import org.apache.flink.streaming.api.watermark.Watermark
 import org.apache.flink.api.common.typeinfo.TypeInformation
 import org.apache.flink.api.common.ExecutionConfig
+import org.apache.flink.api.common.serialization.SerializerConfigImpl
 import org.apache.flink.api.common.state.ReducingStateDescriptor
 import org.apache.flink.util.Collector
 
 import java.util.concurrent.TimeUnit
-
 import scala.collection.JavaConverters.*
 
 class CustomTriggerTest extends AnyFlatSpec with Matchers with Inspectors:
 
   it should "test custom trigger" in {
-    val cfg        = ExecutionConfig()
+    val cfg        = new SerializerConfigImpl()
     val serializer = deriveTypeInformation[TestEvent].createSerializer(
       cfg
     )

modules/flink-1-api/src/main/scala/org/apache/flinkx/api/AllWindowedStream.scala

@@ -6,20 +6,20 @@ import org.apache.flink.api.common.typeinfo.TypeInformation
 import org.apache.flink.streaming.api.datastream.{AllWindowedStream => JavaAllWStream}
 import org.apache.flink.streaming.api.functions.aggregation.AggregationFunction.AggregationType
 import org.apache.flink.streaming.api.functions.aggregation.{ComparableAggregator, SumAggregator}
+import org.apache.flink.streaming.api.windowing.evictors.Evictor
+import org.apache.flink.streaming.api.windowing.time.Time
+import org.apache.flink.streaming.api.windowing.triggers.Trigger
+import org.apache.flink.streaming.api.windowing.windows.Window
+import org.apache.flink.util.Collector
+import org.apache.flink.util.Preconditions.checkNotNull
+import org.apache.flinkx.api.ScalaStreamOps._
 import org.apache.flinkx.api.function.util.{
   ScalaAllWindowFunction,
   ScalaAllWindowFunctionWrapper,
   ScalaProcessAllWindowFunctionWrapper,
   ScalaReduceFunction
 }
 import org.apache.flinkx.api.function.{AllWindowFunction, ProcessAllWindowFunction}
-import org.apache.flink.streaming.api.windowing.evictors.Evictor
-import org.apache.flink.streaming.api.windowing.time.Time
-import org.apache.flink.streaming.api.windowing.triggers.Trigger
-import org.apache.flink.streaming.api.windowing.windows.Window
-import org.apache.flink.util.Collector
-import org.apache.flink.util.Preconditions.checkNotNull
-import ScalaStreamOps._
 
 /** A [[AllWindowedStream]] represents a data stream where the stream of elements is split into windows based on a
   * [[org.apache.flink.streaming.api.windowing.assigners.WindowAssigner]]. Window emission is triggered based on a