content: /*
   *  Copyright 1999-2021 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.selector;
  
  import com.alibaba.nacos.api.exception.NacosException;
  import com.fasterxml.jackson.annotation.JsonTypeInfo;
  
  import java.io.Serializable;
  
  /**
   * The {@link Selector} mainly work on the logic of parse and select.
   * {@link #parse(Object)} allow user accept the condition which provided by Nacos to build the {@link #select(Object)} judge logic.
   * {@link #select(Object)} allow user to execute the logic to get the target result they want.
   * {@link #getType()} will return the type.
   * {@link #getContextType()} will return the context type which used by {@link #select(Object)}.
   *
   * <p>
   *     Now, Nacos only provide the {@link AbstractCmdbSelector} for user to implement their own select logic. Other type is waiting.
   * </p>
   *
   * @author chenglu
   * @date 2021-07-09 21:24
   */
  @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type")
  public interface Selector<R, C, E> extends Serializable {
      
      /**
       * parse the selector, build the inner info which used by {@link #select(Object)}.
       *
       * @param expression expression.
       * @return selector.
       * @throws NacosException parse failed exception.
       */
      Selector<R, C, E> parse(E expression) throws NacosException;
      
      /**
       * select the target result.
       *
       * @param context selector context.
       * @return select result.
       */
      R select(C context);
      
      /**
       * Get the selector type.
       *
       * @return selector type.
       */
      String getType();
      
      /**
       * Get the select context which used by {@link #select(Object)}.
       *
       * @return selector context type.
       */
      String getContextType();
  }
  