add setJoinSubsetType to inject joinSubsetType to BeamSqlSeekableTable

CHANGES.md

@@ -75,6 +75,7 @@
 * Removed fastjson library dependency for Beam SQL. Table property is changed to be based on jackson ObjectNode (Java) ([#24154](https://github.com/apache/beam/issues/24154)).
 * Removed TensorFlow from Beam Python container images [PR](https://github.com/apache/beam/pull/28424). If you have been negatively affected by this change, please comment on [#20605](https://github.com/apache/beam/issues/20605).
 * Removed the parameter `t reflect.Type` from `parquetio.Write`. The element type is derived from the input PCollection (Go) ([#28490](https://github.com/apache/beam/issues/28490))
+* Refactor BeamSqlSeekableTable.setUp adding a parameter joinSubsetType. [#28283](https://github.com/apache/beam/issues/28283)
 
 ## Deprecations
 

sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/BeamSqlSeekableTable.java

@@ -20,6 +20,7 @@
 import java.io.Serializable;
 import java.util.List;
 import org.apache.beam.sdk.options.PipelineOptions;
+import org.apache.beam.sdk.schemas.Schema;
 import org.apache.beam.sdk.transforms.DoFn;
 import org.apache.beam.sdk.values.Row;
 
@@ -28,8 +29,12 @@
  * FROM FACT_TABLE JOIN LOOKUP_TABLE ON ...}.
  */
 public interface BeamSqlSeekableTable extends Serializable {
-  /** prepare the instance. */
-  default void setUp() {}
+  /**
+   * prepare the instance.
+   *
+   * @param joinSubsetType joining subset schema
+   */
+  default void setUp(Schema joinSubsetType) {}
 
   default void startBundle(
       DoFn<Row, Row>.StartBundleContext context, PipelineOptions pipelineOptions) {}

sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/transform/BeamJoinTransforms.java

@@ -153,7 +153,7 @@ public PCollection<Row> expand(PCollection<Row> input) {
                   new DoFn<Row, Row>() {
                     @Setup
                     public void setup() {
-                      seekableTable.setUp();
+                      seekableTable.setUp(joinSubsetType);
                     }
 
                     @StartBundle

sdks/java/extensions/sql/src/test/java/org/apache/beam/sdk/extensions/sql/impl/rel/BeamSideInputLookupJoinRelTest.java

@@ -34,6 +34,7 @@
 import org.apache.beam.sdk.values.POutput;
 import org.apache.beam.sdk.values.Row;
 import org.hamcrest.core.StringContains;
+import org.junit.Assert;
 import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
@@ -47,11 +48,18 @@ public class BeamSideInputLookupJoinRelTest extends BaseRelTest {
 
   /** Test table for JOIN-AS-LOOKUP. */
   public static class SiteLookupTable extends SchemaBaseBeamTable implements BeamSqlSeekableTable {
+    private Schema joinSubsetType;
 
     public SiteLookupTable(Schema schema) {
       super(schema);
     }
 
+    @Override
+    public void setUp(Schema joinSubsetType) {
+      this.joinSubsetType = joinSubsetType;
+      Assert.assertNotNull(joinSubsetType);
+    }
+
     @Override
     public PCollection.IsBounded isBounded() {
       return PCollection.IsBounded.BOUNDED;
@@ -69,6 +77,7 @@ public POutput buildIOWriter(PCollection<Row> input) {
 
     @Override
     public List<Row> seekRow(Row lookupSubRow) {
+      Assert.assertEquals(joinSubsetType, lookupSubRow.getSchema());
       if (lookupSubRow.getInt32("site_id") == 2) {
         return Arrays.asList(Row.withSchema(getSchema()).addValues(2, "SITE1").build());
       }