content: /*
   * Copyright 1999-2020 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.core.v2.client.factory;
  
  import com.alibaba.nacos.common.spi.NacosServiceLoader;
  import com.alibaba.nacos.common.utils.StringUtils;
  import com.alibaba.nacos.naming.constants.ClientConstants;
  import com.alibaba.nacos.naming.misc.Loggers;
  
  import java.util.Collection;
  import java.util.HashMap;
  
  /**
   * Client factory holder.
   *
   * @author xiweng.yy
   */
  public class ClientFactoryHolder {
      
      private static final ClientFactoryHolder INSTANCE = new ClientFactoryHolder();
      
      private final HashMap<String, ClientFactory> clientFactories;
      
      private ClientFactoryHolder() {
          clientFactories = new HashMap<>(4);
          Collection<ClientFactory> clientFactories = NacosServiceLoader.load(ClientFactory.class);
          for (ClientFactory each : clientFactories) {
              if (this.clientFactories.containsKey(each.getType())) {
                  Loggers.SRV_LOG.warn("Client type {} found multiple factory, use {} default", each.getType(),
                          each.getClass().getCanonicalName());
              }
              this.clientFactories.put(each.getType(), each);
          }
      }
      
      public static ClientFactoryHolder getInstance() {
          return INSTANCE;
      }
      
      /**
       * Find target type {@link ClientFactory}.
       *
       * @param type target type
       * @return target type {@link ClientFactory}, if not fount, return 'default' client factory.
       */
      public ClientFactory findClientFactory(String type) {
          if (StringUtils.isEmpty(type) || !clientFactories.containsKey(type)) {
              return clientFactories.get(ClientConstants.DEFAULT_FACTORY);
          }
          return clientFactories.get(type);
      }
  }
  