content: /*
   * Copyright (c) OSGi Alliance 2015. All Rights Reserved.
   *
   * Licensed 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.osgi.service.async;
  
  import org.osgi.annotation.versioning.ProviderType;
  import org.osgi.framework.ServiceReference;
  import org.osgi.util.promise.Promise;
  
  /**
   * The Async Service, as defined in OSGi RFC 204
   * https://github.com/osgi/design/tree/master/rfcs/rfc0206
   */
  @ProviderType
  public interface Async {
      
      /**
       * Create a mediated object for asynchronous calls
       *
       * @param target The object to mediate
       * @param iface The type that the mediated object should implement or extend
       * @return A mediated object
       * @throws IllegalArgumentException if mediation fails
       */
      <T> T mediate(T target, Class<T> iface);
      
      /**
       * Create a mediated object for asynchronous calls
       *
       * @param target The service reference to mediate
       * @param iface The type that the mediated object should implement or extend
       * @return A mediated service
       * @throws IllegalArgumentException if mediation fails
       */
      <T> T mediate(ServiceReference<? extends T> target, Class<T> iface);
      
      /**
       * Asynchronously run the last method call registered by a mediated object,
       * returning the result as a Promise.
       *
       * @param r the return value of the mediated call
       * @return a Promise
       */
      <R> Promise<R> call(R r);
      
      /**
       * Asynchronously run the last method call registered by a mediated object,
       * returning the result as a Promise.
       *
       * @return a Promise
       */
      Promise<?> call();
      
      /**
       * Asynchronously run the last method call registered by a mediated object,
       * ignoring the return value.
       *
       * @return a Promise indicating whether the task started successfully
       */
      Promise<Void> execute();
      
  }
  