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.apollo;
  
  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 Apollo configuration center.
   */
  public class ApolloConfigurationProvider extends AbstractConfigurationProvider {
      private ApolloConfigurationCenterSettings settings;
  
      @Override
      public String name() {
          return "apollo";
      }
  
      @Override
      public ConfigCreator newConfigCreator() {
          return new ConfigCreator<ApolloConfigurationCenterSettings>() {
              @Override
              public Class type() {
                  return ApolloConfigurationCenterSettings.class;
              }
  
              @Override
              public void onInitialized(final ApolloConfigurationCenterSettings initialized) {
                  settings = initialized;
              }
          };
      }
  
      @Override
      protected ConfigWatcherRegister initConfigReader() throws ModuleStartException {
          final String apolloCluster = settings.getApolloCluster();
  
          if (!Strings.isNullOrEmpty(apolloCluster)) {
              System.setProperty("apollo.cluster", apolloCluster);
          }
  
          final String apolloMeta = settings.getApolloMeta();
  
          if (!Strings.isNullOrEmpty(apolloMeta)) {
              System.setProperty("apollo.meta", apolloMeta);
          }
  
          final String appId = settings.getAppId();
  
          if (!Strings.isNullOrEmpty(appId)) {
              System.setProperty("app.id", appId);
          }
  
          final String env = settings.getApolloEnv();
  
          if (!Strings.isNullOrEmpty(env)) {
              System.setProperty("env", env);
          }
  
          return new ApolloConfigWatcherRegister(settings);
      }
  }
  