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.naming.consistency;
  
  import com.alibaba.nacos.naming.pojo.Record;
  
  /**
   * Data listener public interface
   *
   * @author nacos
   */
  public interface RecordListener<T extends Record> {
  
      /**
       * Determine if the listener was registered with this key
       *
       * @param key candidate key
       * @return true if the listener was registered with this key
       */
      boolean interests(String key);
  
      /**
       * Determine if the listener is to be removed by matching the 'key'
       *
       * @param key key to match
       * @return true if match success
       */
      boolean matchUnlistenKey(String key);
  
      /**
       * Action to do if data of target key has changed
       *
       * @param key   target key
       * @param value data of the key
       * @throws Exception
       */
      void onChange(String key, T value) throws Exception;
  
      /**
       * Action to do if data of target key has been removed
       *
       * @param key target key
       * @throws Exception
       */
      void onDelete(String key) throws Exception;
  }
  