content: /*
   * 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.bookkeeper.common.component;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.concurrent.ConcurrentHashMap;
  import lombok.extern.slf4j.Slf4j;
  
  /**
   * Allows a component to publish information about
   * the services it implements, the endpoints it exposes
   * and other useful information for management tools and client.
   */
  @Slf4j
  public class ComponentInfoPublisher {
  
      private final Map<String, String> properties = new ConcurrentHashMap<>();
      private final Map<String, EndpointInfo> endpoints = new ConcurrentHashMap<>();
  
      /**
       * Endpoint information.
       */
      public static final class EndpointInfo {
  
          private final String id;
          private final int port;
          private final String host;
          private final String protocol;
          private final List<String> auth;
          private final List<String> extensions;
  
          public EndpointInfo(String id, int port, String host, String protocol,
                              List<String> auth, List<String> extensions) {
              this.id = id;
              this.port = port;
              this.host = host;
              this.protocol = protocol;
              this.auth = auth == null ? Collections.emptyList() : Collections.unmodifiableList(auth);
              this.extensions = extensions == null ? Collections.emptyList() : Collections.unmodifiableList(extensions);
          }
  
          public String getId() {
              return id;
          }
  
          public int getPort() {
              return port;
          }
  
          public String getHost() {
              return host;
          }
  
          public String getProtocol() {
              return protocol;
          }
  
          public List<String> getAuth() {
              return auth;
          }
  
          public List<String> getExtensions() {
              return extensions;
          }
  
          @Override
          public String toString() {
              return "EndpointInfo{" + "id=" + id + ", port=" + port + ", host=" + host + ", protocol=" + protocol + ", "
                      + "auth=" + auth + ", extensions=" + extensions + '}';
          }
  
      }
  
      private volatile boolean startupFinished;
  
      /**
       * Publish an information about the system, like an endpoint address.
       *
       * @param key the key
       * @param value the value, null values are not allowed.
       */
      public void publishProperty(String key, String value) {
          if (log.isDebugEnabled()) {
              log.debug("publish {}={}", key, value);
          }
          if (startupFinished) {
              throw new IllegalStateException("Server already started, cannot publish " + key);
          }
          Objects.requireNonNull(key);
          Objects.requireNonNull(value, "Value for " + key + " cannot be null");
  
          properties.put(key, value);
      }
  
      public void publishEndpoint(EndpointInfo endpoint) {
          if (log.isDebugEnabled()) {
              log.debug("publishEndpoint {} on {}", endpoint, this);
          }
          EndpointInfo exists = endpoints.put(endpoint.id, endpoint);
          if (exists != null) {
              throw new IllegalStateException("An endpoint with id " + endpoint.id
                      + " has already been published: " + exists);
          }
      }
  
      public Map<String, String> getProperties() {
          if (!startupFinished) {
              throw new IllegalStateException("Startup not yet finished");
          }
          return Collections.unmodifiableMap(properties);
      }
  
      public Map<String, EndpointInfo> getEndpoints() {
          if (!startupFinished) {
              throw new IllegalStateException("Startup not yet finished");
          }
          return Collections.unmodifiableMap(endpoints);
      }
  
      /**
       * Called by the framework to signal that preparation of startup is done,
       * so we have gathered all of the available information.
       */
      public void startupFinished() {
          startupFinished = true;
      }
  
  }
  