code: /*
   * 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.skywalking.oap.server.configuration.zookeeper;
  
  import com.google.common.base.Strings;
  import org.apache.skywalking.oap.server.configuration.api.AbstractConfigurationProvider;
  import org.apache.skywalking.oap.server.configuration.api.ConfigWatcherRegister;
  import org.apache.skywalking.oap.server.library.module.ModuleStartException;
  
  /**
   * Get configuration from Zookeeper.
   */
  public class ZookeeperConfigurationProvider extends AbstractConfigurationProvider {
      private ZookeeperServerSettings settings;
  
      @Override
      public String name() {
          return "zookeeper";
      }
  
      @Override
      public ConfigCreator newConfigCreator() {
          return new ConfigCreator<ZookeeperServerSettings>() {
              @Override
              public Class type() {
                  return ZookeeperServerSettings.class;
              }
  
              @Override
              public void onInitialized(final ZookeeperServerSettings initialized) {
                  settings = initialized;
              }
          };
      }
  
      @Override
      protected ConfigWatcherRegister initConfigReader() throws ModuleStartException {
          if (Strings.isNullOrEmpty(settings.getHostPort())) {
              throw new ModuleStartException("Zookeeper hostPort cannot be null or empty.");
          }
          if (Strings.isNullOrEmpty(settings.getNamespace())) {
              throw new ModuleStartException("Zookeeper namespace cannot be null or empty.");
          }
  
          try {
              return new ZookeeperConfigWatcherRegister(settings);
          } catch (Exception e) {
              throw new ModuleStartException(e.getMessage(), e);
          }
      }
  }
  