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 org.apache.ambari.server.events.publishers;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.ambari.server.AmbariRuntimeException;
  import org.apache.ambari.server.events.DefaultMessageEmitter;
  import org.apache.ambari.server.events.STOMPEvent;
  import org.apache.ambari.server.utils.ThreadPools;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.google.common.eventbus.AsyncEventBus;
  import com.google.common.eventbus.EventBus;
  import com.google.inject.Singleton;
  
  @Singleton
  @SuppressWarnings({"UnstableApiUsage", "rawtypes"})
  public class STOMPUpdatePublisher {
    private static final Logger LOG = LoggerFactory.getLogger(STOMPUpdatePublisher.class);
  
    private final EventBus agentEventBus;
    private final EventBus apiEventBus;
  
    private final List<BufferedUpdateEventPublisher> publishers = new ArrayList<>();
  
  
    public STOMPUpdatePublisher() {
      agentEventBus = new AsyncEventBus("agent-update-bus", ThreadPools.getSingleThreadedExecutor("stomp-agent-bus"));
      apiEventBus = new AsyncEventBus("api-update-bus", ThreadPools.getSingleThreadedExecutor("stomp-api-bus"));
    }
  
    public void registerPublisher(BufferedUpdateEventPublisher publisher) {
      if (publishers.contains(publisher)) {
        LOG.error("Publisher for type {} is already in use", publisher.getType());
      } else {
        publishers.add(publisher);
      }
    }
  
    public void publish(STOMPEvent event) {
      if (DefaultMessageEmitter.DEFAULT_AGENT_EVENT_TYPES.contains(event.getType())) {
        publishAgent(event);
      } else if (DefaultMessageEmitter.DEFAULT_API_EVENT_TYPES.contains(event.getType())) {
        publishAPI(event);
      } else {
        // TODO need better solution
        throw new AmbariRuntimeException("Event with type {" + event.getType() + "} can not be published.");
      }
    }
  
    @SuppressWarnings("unchecked")
    private void publishAPI(STOMPEvent event) {
      boolean published = false;
      for (BufferedUpdateEventPublisher publisher : publishers) {
        if (publisher.getType().equals(event.getType())) {
          publisher.publish(event, apiEventBus);
          published = true;
        }
      }
      if (!published) {
        apiEventBus.post(event);
      }
    }
  
    private void publishAgent(STOMPEvent event) {
      agentEventBus.post(event);
    }
  
    public void registerAgent(Object object) {
      agentEventBus.register(object);
    }
  
    public void registerAPI(Object object) {
      apiEventBus.register(object);
    }
  }
  