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.core.worker;
  
  import java.util.HashMap;
  import java.util.Map;
  import org.apache.skywalking.oap.server.core.UnexpectedException;
  import org.apache.skywalking.oap.server.core.remote.data.StreamData;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Worker Instance Service hosts all remote handler workers with the stream data type.
   */
  public class WorkerInstancesService implements IWorkerInstanceSetter, IWorkerInstanceGetter {
      private static final Logger LOGGER = LoggerFactory.getLogger(WorkerInstancesService.class);
  
      private final Map<String, RemoteHandleWorker> instances;
  
      public WorkerInstancesService() {
          this.instances = new HashMap<>();
      }
  
      @Override
      public RemoteHandleWorker get(String nextWorkerName) {
          return instances.get(nextWorkerName);
      }
  
      @Override
      public void put(String remoteReceiverWorkName, AbstractWorker instance,
          Class<? extends StreamData> streamDataClass) {
          if (instances.containsKey(remoteReceiverWorkName)) {
              throw new UnexpectedException("Duplicate worker name:" + remoteReceiverWorkName);
          }
          instances.put(remoteReceiverWorkName, new RemoteHandleWorker(instance, streamDataClass));
          LOGGER.debug("Worker {} has been registered as {}", instance.toString(), remoteReceiverWorkName);
      }
  }
  