frankgh commented on code in PR #72: URL: https://github.com/apache/cassandra-sidecar/pull/72#discussion_r1367521384
########## src/main/java/org/apache/cassandra/sidecar/server/SidecarServerEvents.java: ########## @@ -0,0 +1,131 @@ +/* + * 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.sidecar.server; + +import java.util.Collections; +import java.util.HashSet; +import java.util.Set; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import com.google.inject.Inject; +import com.google.inject.Singleton; +import io.vertx.core.Vertx; +import io.vertx.core.eventbus.EventBus; +import io.vertx.core.eventbus.MessageConsumer; +import io.vertx.core.json.JsonArray; +import io.vertx.core.json.JsonObject; +import org.apache.cassandra.sidecar.cluster.InstancesConfig; +import org.apache.cassandra.sidecar.cluster.instance.InstanceMetadata; + +/** + * Defines the {@link io.vertx.core.eventbus.EventBus} addresses where different notifications will be published + * during Sidecar startup/shutdown, as well as CQL connection availability. + * + * <p>The messages can be published multiple times depending on whether Sidecar is started or stopped + * during the lifetime of the application. Implementing consumers will need to deal with this expectation + * internally. + * <p> + * The expectation is that: + * <ul> + * <li>{@link #ON_SERVER_START} will happen first + * <li>{@link #ON_SERVER_STOP} can happen before {@link #ON_ALL_CASSANDRA_CQL_READY} + * <li>{@link #ON_SERVER_START} can only happen for any subsequent calls only after a {@link #ON_SERVER_STOP} message + * <li>{@link #ON_ALL_CASSANDRA_CQL_READY} might never happen + * <li>{@link #ON_CASSANDRA_CQL_READY} can be called multiple times with different cassandraInstanceId values + * <li>{@link #ON_CASSANDRA_CQL_DISCONNECTED} can be called multiple times with different cassandraInstanceId values + * </ul> + * <p> + * However, implementers should choose to implement methods assuming no guarantees to the event sequence. + */ +@Singleton +public class SidecarServerEvents +{ + private static final Logger LOGGER = LoggerFactory.getLogger(SidecarServerEvents.class); + + /** + * The {@link io.vertx.core.eventbus.EventBus} address where server start events will be published. Server start + * will be published whenever Sidecar has successfully started and is ready listening for requests. + */ + public static final String ON_SERVER_START = SidecarServerEvents.class.getName() + ".ON_SERVER_START"; + + /** + * The {@link io.vertx.core.eventbus.EventBus} address where server stop/shutdown events will be published. + * Server stop events will be published whenever Sidecar is stopping or shutting down. + */ + public static final String ON_SERVER_STOP = SidecarServerEvents.class.getName() + ".ON_SERVER_STOP"; + + /** + * The {@link io.vertx.core.eventbus.EventBus} address where events will be published when a CQL connection for + * a given instance has been established. The instance identifier will be passed as part of the message. + */ + public static final String ON_CASSANDRA_CQL_READY = SidecarServerEvents.class.getName() + ".ON_CASSANDRA_CQL_READY"; Review Comment: makes sense, refactored -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
