fix jdbc transform validation

sdks/java/io/jdbc/src/main/java/org/apache/beam/sdk/io/jdbc/JdbcReadSchemaTransformProvider.java

@@ -214,7 +214,7 @@ protected JdbcIO.DataSourceConfiguration dataSourceConfiguration() {
 
     @Override
     public PCollectionRowTuple expand(PCollectionRowTuple input) {
-      config.validate();
+      config.validate(jdbcType);
       // If we define a partition column, we follow a different route.
       @Nullable String partitionColumn = config.getPartitionColumn();
       @Nullable String location = config.getLocation();

sdks/java/io/jdbc/src/test/java/org/apache/beam/sdk/io/jdbc/JdbcReadSchemaTransformProviderTest.java

@@ -22,6 +22,7 @@
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThrows;
 
+import com.google.auto.service.AutoService;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
@@ -47,6 +48,25 @@
 @RunWith(JUnit4.class)
 public class JdbcReadSchemaTransformProviderTest {
 
+  @AutoService(SchemaTransformProvider.class)
+  public static class ReadFromDerbySchemaTransformProvider extends JdbcReadSchemaTransformProvider {
+
+    @Override
+    public String identifier() {
+      return "beam:schematransform:org.apache.beam:derby_read:v1";
+    }
+
+    @Override
+    public String description() {
+      return inheritedDescription("Derby", "ReadFromDerby", "derby", 5432);
+    }
+
+    @Override
+    protected String jdbcType() {
+      return "derby";
+    }
+  }
+
   private static final JdbcIO.DataSourceConfiguration DATA_SOURCE_CONFIGURATION =
       JdbcIO.DataSourceConfiguration.create(
           "org.apache.derby.jdbc.EmbeddedDriver", "jdbc:derby:memory:testDB;create=true");
@@ -199,6 +219,32 @@ public void testReadWithJdbcTypeSpecified() {
     pipeline.run();
   }
 
+  @Test
+  public void testReadWithJdbcDerbyTransformTypeSpecified() {
+    JdbcReadSchemaTransformProvider provider = null;
+    for (SchemaTransformProvider p : ServiceLoader.load(SchemaTransformProvider.class)) {
+      if (p instanceof ReadFromDerbySchemaTransformProvider) {
+        provider = (JdbcReadSchemaTransformProvider) p;
+        break;
+      }
+    }
+    assertNotNull(provider);
+
+    PCollection<Row> output =
+        PCollectionRowTuple.empty(pipeline)
+            .apply(
+                provider.from(
+                    ReadFromDerbySchemaTransformProvider.JdbcReadSchemaTransformConfiguration
+                        .builder()
+                        .setJdbcUrl(DATA_SOURCE_CONFIGURATION.getUrl().get())
+                        .setLocation(READ_TABLE_NAME)
+                        .build()))
+            .get("output");
+    Long expected = Long.valueOf(EXPECTED_ROW_COUNT);
+    PAssert.that(output.apply(Count.globally())).containsInAnyOrder(expected);
+    pipeline.run();
+  }
+
   @Test
   public void testReadWithPartitions() {
     JdbcReadSchemaTransformProvider provider = null;