kennknowles commented on a change in pull request #13200: URL: https://github.com/apache/beam/pull/13200#discussion_r513086568
########## File path: sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/UdfProvider.java ########## @@ -0,0 +1,39 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.beam.sdk.extensions.sql; + +import java.lang.reflect.Method; +import java.util.Collections; +import java.util.Map; +import org.apache.beam.sdk.transforms.Combine; + +/** + * Provider for user-defined functions written in Java. Implementations should be annotated with + * {@link com.google.auto.service.AutoService}. + */ +public interface UdfProvider { + /** Maps function names to scalar function implementations. */ + default Map<String, Method> userDefinedScalarFunctions() { Review comment: I don't agree. If it is a simple function, a method can always be used as in `SomeClass::methodName` and this is also easier for following control flow (including for IDEs). Whenever you can use explicit method references instead of reflection, you should. The converse is not true. If a function is provided, it cannot automatically be converted to `Method`. The class `Method` is specifically a rich representation of an aspect of a `Class` in the JVM. It is not a good class for use when you want some sort of function. It is not a good class for anything _except_ when you specifically want to manipulate the JVM's representation of a class. If we expand the interface, we can maintain backwards-compatibility with `default` method implementation. If we need to expand it in a way where this is not possible we will need to create a new interface. If we use `Method` it is not possible to expand the interface anyhow. I really think if you look at the pro/con of using `Method` vs a smaller interface there is not a single thing in the "pro" column. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
