code: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.skywalking.oap.server.library.datacarrier.consumer;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.Callable;
  
  /**
   * Consumer Pool Factory provides global management for all Consumer Pool.
   */
  public enum ConsumerPoolFactory {
      INSTANCE;
  
      private final Map<String, ConsumerPool> pools;
  
      ConsumerPoolFactory() {
          pools = new HashMap<>();
      }
  
      public synchronized boolean createIfAbsent(String poolName, Callable<ConsumerPool> creator) throws Exception {
          if (pools.containsKey(poolName)) {
              return false;
          } else {
              pools.put(poolName, creator.call());
              return true;
          }
      }
  
      public ConsumerPool get(String poolName) {
          return pools.get(poolName);
      }
  
  }
  