content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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 com.alibaba.nacos.client.naming.core;
  
  import com.alibaba.nacos.api.exception.NacosException;
  import com.alibaba.nacos.api.exception.runtime.NacosLoadException;
  import com.alibaba.nacos.client.address.AbstractServerListManager;
  import com.alibaba.nacos.client.address.PropertiesListProvider;
  import com.alibaba.nacos.client.env.NacosClientProperties;
  import com.alibaba.nacos.client.naming.remote.http.NamingHttpClientManager;
  import com.alibaba.nacos.client.utils.LogUtils;
  import com.alibaba.nacos.common.JustForTest;
  import com.alibaba.nacos.common.http.client.NacosRestTemplate;
  import org.slf4j.Logger;
  
  import java.util.List;
  import java.util.Properties;
  import java.util.Random;
  import java.util.concurrent.atomic.AtomicInteger;
  
  /**
   * Naming server list manager.
   *
   * @author xiweng.yy
   */
  public class NamingServerListManager extends AbstractServerListManager {
      
      private static final Logger LOGGER = LogUtils.logger(NamingServerListManager.class);
      
      private final AtomicInteger currentIndex = new AtomicInteger();
      
      private String nacosDomain;
      
      private boolean isDomain;
      
      @JustForTest
      public NamingServerListManager(Properties properties) {
          this(NacosClientProperties.PROTOTYPE.derive(properties), "");
      }
      
      public NamingServerListManager(NacosClientProperties properties, String namespace) {
          super(properties, namespace);
      }
      
      @Override
      public void start() throws NacosException {
          super.start();
          List<String> serverList = getServerList();
          if (serverList.isEmpty()) {
              throw new NacosLoadException("serverList is empty,please check configuration");
          } else {
              currentIndex.set(new Random().nextInt(serverList.size()));
          }
          if (serverListProvider instanceof PropertiesListProvider) {
              if (serverList.size() == 1) {
                  isDomain = true;
                  nacosDomain = serverList.get(0);
              }
          }
      }
      
      public String getNacosDomain() {
          return nacosDomain;
      }
      
      public boolean isDomain() {
          return isDomain;
      }
      
      @Override
      protected String getModuleName() {
          return "Naming";
      }
      
      @Override
      protected NacosRestTemplate getNacosRestTemplate() {
          return NamingHttpClientManager.getInstance().getNacosRestTemplate();
      }
      
      @Override
      public String genNextServer() {
          int index = currentIndex.incrementAndGet() % getServerList().size();
          return getServerList().get(index);
      }
      
      @Override
      public String getCurrentServer() {
          return getServerList().get(currentIndex.get() % getServerList().size());
      }
  }
  