andrew4699 commented on code in PR #922: URL: https://github.com/apache/polaris/pull/922#discussion_r1988293832
########## service/common/src/main/java/org/apache/polaris/service/events/PolarisEventListener.java: ########## @@ -0,0 +1,49 @@ +/* + * 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.polaris.service.events; + +/** + * Represents an event listener that can respond to notable moments during Polaris's execution. + * Users can either extend this interface and implement handlers for all events or, for ease, extend + * DefaultPolarisEventListener and only have to handle a subset of events. Event details are + * documented under the event objects themselves. + */ +public interface PolarisEventListener { Review Comment: I'm happy to disagree & commit to one option here and do this iteratively, but let me make 1 more case for the current approach: Spark does almost exactly what this does. [SparkListenerInterface is public](https://spark.apache.org/docs/3.5.4/api/java/org/apache/spark/scheduler/SparkListenerInterface.html) and they just recommend against using it. The only difference in Spark is that SparkListener (our DefaultPolarisEventListener) is abstract. However, I'm not sure if we have an elegant way to specify "no event listener" with our config singleton pattern, so a non-abstract default listener may actually be needed. > If the interface PolarisEventListener is public, it's part of the API. If it's part of the API, you cannot add regular methods to it, even if you implement them in DefaultPolarisEventListener. I think as a general rule it's good to apply this principle, but users are getting an explicit warning here. We could make the warning even louder. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
