[BEAM-14139] Drop support for Flink 1.11.

gradle.properties

@@ -37,5 +37,5 @@ javaVersion=1.8
 docker_image_default_repo_root=apache
 docker_image_default_repo_prefix=beam_
 
-flink_versions=1.11,1.12,1.13,1.14
+flink_versions=1.12,1.13,1.14
 

runners/flink/1.12/build.gradle

@@ -22,8 +22,8 @@ project.ext {
   // Set the version of all Flink-related dependencies here.
   flink_version = '1.12.7'
   // Version specific code overrides.
-  main_source_overrides = ["${basePath}/1.11/src/main/java", './src/main/java']
-  test_source_overrides = ["${basePath}/1.11/src/test/java", './src/test/java']
+  main_source_overrides = ['./src/main/java']
+  test_source_overrides = ['./src/test/java']
   main_resources_overrides = []
   test_resources_overrides = []
   archives_base_name = 'beam-runners-flink-1.12'

runners/flink/1.12/src/test/java/org/apache/beam/runners/flink/streaming/StreamSources.java

@@ -17,40 +17,20 @@
  */
 package org.apache.beam.runners.flink.streaming;
 
-import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Iterables;
-import org.apache.flink.api.dag.Transformation;
 import org.apache.flink.runtime.operators.testutils.MockEnvironmentBuilder;
 import org.apache.flink.streaming.api.functions.source.SourceFunction;
 import org.apache.flink.streaming.api.operators.AbstractStreamOperator;
 import org.apache.flink.streaming.api.operators.Output;
 import org.apache.flink.streaming.api.operators.StreamSource;
-import org.apache.flink.streaming.api.transformations.OneInputTransformation;
 import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
 import org.apache.flink.streaming.runtime.streamstatus.StreamStatus;
 import org.apache.flink.streaming.runtime.streamstatus.StreamStatusMaintainer;
 import org.apache.flink.streaming.runtime.tasks.OperatorChain;
 import org.apache.flink.streaming.runtime.tasks.StreamTask;
 
-/**
- * {@link StreamSource} utilities, that bridge incompatibilities between Flink releases.
- *
- * <p>This change is becauses RecordWriter is wrapped in RecordWriterDelegate in 1.10, please refer
- * to https://github.com/apache/flink/commit/2c8b4ef572f05bf4740b7e204af1e5e709cd945c for more
- * details.
- */
+/** {@link StreamSource} utilities, that bridge incompatibilities between Flink releases. */
 public class StreamSources {
 
-  /**
-   * Backward compatibility helper for {@link OneInputTransformation} `getInput` method, that has
-   * been removed in Flink 1.12.
-   *
-   * @param source Source to get single input from.
-   * @return Input transformation.
-   */
-  public static Transformation<?> getOnlyInput(OneInputTransformation<?, ?> source) {
-    return Iterables.getOnlyElement(source.getInputs());
-  }
-
   public static <OutT, SrcT extends SourceFunction<OutT>> void run(
       StreamSource<OutT, SrcT> streamSource,
       Object lockingObject,

runners/flink/1.13/build.gradle

@@ -22,8 +22,8 @@ project.ext {
   // Set the version of all Flink-related dependencies here.
   flink_version = '1.13.5'
   // Version specific code overrides.
-  main_source_overrides = ["${basePath}/1.11/src/main/java", "${basePath}/1.12/src/main/java", './src/main/java']
-  test_source_overrides = ["${basePath}/1.11/src/test/java", "${basePath}/1.12/src/test/java", './src/test/java']
+  main_source_overrides = ["${basePath}/1.12/src/main/java", './src/main/java']
+  test_source_overrides = ["${basePath}/1.12/src/test/java", './src/test/java']
   main_resources_overrides = []
   test_resources_overrides = []
   archives_base_name = 'beam-runners-flink-1.13'