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.causeway.applib.services.eventbus;
  
  /**
   * A service implementing an Event Bus, allowing domain objects to emit
   * arbitrary events on an in-memory event bus.
   *
   * <p>
   * Events are delivered synchronously to event subscribers (domain services).
   * </p>
   *
   * @since 2.0 {@index}
   */
  public interface EventBusService {
  
      /**
       * Post an event (of any class) to the in-memory event bus.
       *
       * <p>
       *     The event will be delivered synchronously (within the same
       *     transactional boundary) to all subscribers of that event type
       *     (with subscribers as domain services with public method annotated
       *     using Spring's
       *     {@link org.springframework.context.event.EventListener} annotation.
       * </p>
       */
      void post(Object event);
  
  }
  
  