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.push.v2.executor;
  
  import com.alibaba.nacos.common.spi.NacosServiceLoader;
  import com.alibaba.nacos.naming.pojo.Subscriber;
  
  import java.util.HashSet;
  import java.util.Optional;
  import java.util.Set;
  
  /**
   * SPI push executor holder.
   *
   * @author xiweng.yy
   */
  public class SpiImplPushExecutorHolder {
      
      private static final SpiImplPushExecutorHolder INSTANCE = new SpiImplPushExecutorHolder();
      
      private final Set<SpiPushExecutor> pushExecutors;
      
      private SpiImplPushExecutorHolder() {
          pushExecutors = new HashSet<>(NacosServiceLoader.load(SpiPushExecutor.class));
      }
      
      public static SpiImplPushExecutorHolder getInstance() {
          return INSTANCE;
      }
      
      /**
       * Try to find an {@link PushExecutor} implement by SPI which interest to execute this push.
       *
       * @param clientId   client id
       * @param subscriber subscriber infor
       * @return {@link PushExecutor} which interest to execute this push, otherwise {@code Optional.empty()}
       */
      public Optional<SpiPushExecutor> findPushExecutorSpiImpl(String clientId, Subscriber subscriber) {
          for (SpiPushExecutor each : pushExecutors) {
              if (each.isInterest(clientId, subscriber)) {
                  return Optional.of(each);
              }
          }
          return Optional.empty();
      }
  }
  