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.api.config;
  
  import com.alibaba.nacos.api.config.listener.Listener;
  import com.alibaba.nacos.api.exception.NacosException;
  
  /**
   * Config Service Interface
   *
   * @author Nacos
   */
  public interface ConfigService {
  
      /**
       * Get config
       *
       * @param dataId    dataId
       * @param group     group
       * @param timeoutMs read timeout
       * @return config value
       * @throws NacosException NacosException
       */
      String getConfig(String dataId, String group, long timeoutMs) throws NacosException;
  
      /**
       * Get config and register Listener
       *
       * If you want to pull it yourself when the program starts to get the configuration for the first time,
       * and the registered Listener is used for future configuration updates, you can keep the original
       * code unchanged, just add the system parameter: enableRemoteSyncConfig = "true" ( But there is network overhead);
       * therefore we recommend that you use this interface directly
       *
       * @param dataId    dataId
       * @param group     group
       * @param timeoutMs read timeout
       * @param listener {@link Listener}
       * @return config value
       * @throws NacosException NacosException
       */
      String getConfigAndSignListener(String dataId, String group, long timeoutMs, Listener listener) throws NacosException;
  
      /**
       * Add a listener to the configuration, after the server modified the
       * configuration, the client will use the incoming listener callback.
       * Recommended asynchronous processing, the application can implement the
       * getExecutor method in the ManagerListener, provide a thread pool of
       * execution. If provided, use the main thread callback, May block other
       * configurations or be blocked by other configurations.
       *
       * @param dataId   dataId
       * @param group    group
       * @param listener listener
       * @throws NacosException NacosException
       */
      void addListener(String dataId, String group, Listener listener) throws NacosException;
  
      /**
       * Publish config.
       *
       * @param dataId  dataId
       * @param group   group
       * @param content content
       * @return Whether publish
       * @throws NacosException NacosException
       */
      boolean publishConfig(String dataId, String group, String content) throws NacosException;
  
      /**
       * Remove config
       *
       * @param dataId dataId
       * @param group  group
       * @return whether remove
       * @throws NacosException NacosException
       */
      boolean removeConfig(String dataId, String group) throws NacosException;
  
      /**
       * Remove listener
       *
       * @param dataId   dataId
       * @param group    group
       * @param listener listener
       */
      void removeListener(String dataId, String group, Listener listener);
  
      /**
       * Get server status
       *
       * @return whether health
       */
      String getServerStatus();
  
  }
  