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.bifromq.plugin.eventcollector;
  
  import java.lang.reflect.Modifier;
  import java.util.HashSet;
  import java.util.Set;
  import lombok.SneakyThrows;
  import org.reflections.Reflections;
  
  class EventPool {
      private static final Set<Class<Event<?>>> EVENT_TYPES = new HashSet<>();
      private final Event<?>[] events;
  
      static {
          Reflections reflections = new Reflections(Event.class.getPackageName());
          for (Class<?> eventClass : reflections.getSubTypesOf(Event.class)) {
              if (!Modifier.isAbstract(eventClass.getModifiers())) {
                  EVENT_TYPES.add((Class<Event<?>>) eventClass);
              }
          }
      }
  
      EventPool() {
          events = new Event[EVENT_TYPES.size()];
          EVENT_TYPES.forEach(this::add);
      }
  
      <T extends Event<T>> T get(EventType eventType) {
          return (T) events[eventType.ordinal()];
      }
  
      @SneakyThrows
      private void add(Class<Event<?>> eventClass) {
          Event<?> event = eventClass.getConstructor().newInstance();
          events[event.type().ordinal()] = event;
      }
  }
  