Issue warnings when dataSourceConfiguration and dataSourceProviderFn are set (#34395)

* Issue warnings when withDataSourceConfiguration and withDataSourceProviderFn are set

* spotless

Author: liferoad

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

@@ -778,6 +778,12 @@ public ReadRows withDataSourceConfiguration(DataSourceConfiguration config) {
 
     public ReadRows withDataSourceProviderFn(
         SerializableFunction<Void, DataSource> dataSourceProviderFn) {
+      if (getDataSourceProviderFn() != null
+          && !(getDataSourceProviderFn()
+              instanceof DataSourceProviderFromDataSourceConfiguration)) {
+        LOG.warn(
+            "Both withDataSourceConfiguration and withDataSourceProviderFn are provided. dataSourceProviderFn will override dataSourceConfiguration.");
+      }
       return toBuilder().setDataSourceProviderFn(dataSourceProviderFn).build();
     }
 
@@ -948,6 +954,12 @@ public Read<T> withDataSourceConfiguration(final DataSourceConfiguration config)
 
     public Read<T> withDataSourceProviderFn(
         SerializableFunction<Void, DataSource> dataSourceProviderFn) {
+      if (getDataSourceProviderFn() != null
+          && !(getDataSourceProviderFn()
+              instanceof DataSourceProviderFromDataSourceConfiguration)) {
+        LOG.warn(
+            "Both withDataSourceConfiguration and withDataSourceProviderFn are provided. dataSourceProviderFn will override dataSourceConfiguration.");
+      }
       return toBuilder().setDataSourceProviderFn(dataSourceProviderFn).build();
     }