content: /*
   * Copyright 1999-2023 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.common.paramcheck;
  
  import com.alibaba.nacos.common.spi.NacosServiceLoader;
  import com.alibaba.nacos.common.utils.StringUtils;
  
  import java.util.Collection;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  /**
   * The type Param checker manager.
   *
   * @author zhuoguang
   */
  public class ParamCheckerManager {
      
      private static final ParamCheckerManager INSTANCE = new ParamCheckerManager();
      
      private static final AbstractParamChecker DEFAULT_PARAM_CHECKER = new DefaultParamChecker();
      
      private final Map<String, AbstractParamChecker> paramCheckerMap = new ConcurrentHashMap<>();
      
      private ParamCheckerManager() {
          Collection<AbstractParamChecker> paramCheckers = NacosServiceLoader.load(AbstractParamChecker.class);
          for (AbstractParamChecker paramChecker : paramCheckers) {
              String checkerType = paramChecker.getCheckerType();
              paramCheckerMap.put(checkerType, paramChecker);
          }
      }
      
      public static ParamCheckerManager getInstance() {
          return INSTANCE;
      }
      
      public AbstractParamChecker getParamChecker(String checkerType) {
          if (StringUtils.isBlank(checkerType)) {
              return DEFAULT_PARAM_CHECKER;
          }
          AbstractParamChecker paramChecker = paramCheckerMap.get(checkerType);
          if (paramChecker == null) {
              paramChecker = DEFAULT_PARAM_CHECKER;
          }
          return paramChecker;
      }
  }
  