Mmuzaf commented on code in PR #2334: URL: https://github.com/apache/cassandra/pull/2334#discussion_r1205956790
########## src/java/org/apache/cassandra/config/ListenableProperty.java: ########## @@ -0,0 +1,112 @@ +/* + * 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.cassandra.config; + +import java.util.EnumMap; +import java.util.List; +import java.util.Map; +import java.util.concurrent.CopyOnWriteArrayList; +import java.util.function.BiConsumer; + +import org.yaml.snakeyaml.introspector.Property; + +/** + * + */ +public class ListenableProperty<S, T> extends ForwardingProperty +{ + private final Map<EventType, List<Handler<S, T>>> handlers = new EnumMap<>(EventType.class); + + public ListenableProperty(Property property) + { + super(property.getName(), property); + for (EventType eventType : EventType.values()) + handlers.put(eventType, new CopyOnWriteArrayList<>()); + } + + @SuppressWarnings("unchecked") + @Override + public synchronized void set(Object source, Object newValue) throws Exception + { + T oldValue = (T) get(source); + T value = Handler.compose(handlers.get(EventType.BEFORE)).handle((S) source, oldValue, (T) newValue); + delegate().set(source, value); + Handler.compose(handlers.get(EventType.AFTER)).handle((S) source, oldValue, value); Review Comment: I have added `BeforeChangeListener`, and `AfterChangeListener` instead of the `Handler` as you pointed out above. We can still merge them into a single interface with two methods, `onBefore` and `onAfter`, but in the latter case the API looks like a stateful interface, which I'd like to avoid adding. -- 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: pr-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For additional commands, e-mail: pr-h...@cassandra.apache.org
