content: /**
   * 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 com.alibaba.jstorm.ons.consumer;
  
  import com.aliyun.openservices.ons.api.Consumer;
  import com.aliyun.openservices.ons.api.MessageListener;
  import com.aliyun.openservices.ons.api.ONSFactory;
  import com.aliyun.openservices.ons.api.PropertyKeyConst;
  import org.apache.log4j.Logger;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Properties;
  
  public class ConsumerFactory {
      private static final Logger LOG = Logger.getLogger(ConsumerFactory.class);
  
      public static Map<String, Consumer> consumers = new HashMap<String, Consumer>();
  
      public static synchronized Consumer mkInstance(ConsumerConfig consumerConfig, MessageListener listener) throws Exception {
          String consumerId = consumerConfig.getConsumerId();
          Consumer consumer = consumers.get(consumerId);
          if (consumer != null) {
  
              LOG.info("Consumer of " + consumerId + " has been created, don't recreate it ");
  
              // Attention, this place return null to info duplicated consumer
              return null;
          }
  
          Properties properties = new Properties();
          properties.put(PropertyKeyConst.AccessKey, consumerConfig.getAccessKey());
          properties.put(PropertyKeyConst.SecretKey, consumerConfig.getSecretKey());
          properties.put(PropertyKeyConst.ConsumerId, consumerId);
          properties.put(PropertyKeyConst.ConsumeThreadNums, consumerConfig.getConsumerThreadNum());
          consumer = ONSFactory.createConsumer(properties);
  
          consumer.subscribe(consumerConfig.getTopic(), consumerConfig.getSubExpress(), listener);
          consumer.start();
  
          consumers.put(consumerId, consumer);
          LOG.info("Successfully create " + consumerId + " consumer");
  
          return consumer;
  
      }
  
  }
  