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.beam.runners.direct;
  
  /**
   * Schedules and completes {@link TransformExecutor TransformExecutors}, controlling concurrency as
   * appropriate for the {@link StepAndKey} the executor exists for.
   */
  interface TransformExecutorService {
    /** Schedule the provided work to be eventually executed. */
    void schedule(TransformExecutor work);
  
    /**
     * Finish executing the provided work. This may cause additional {@link DirectTransformExecutor
     * TransformExecutors} to be evaluated.
     */
    void complete(TransformExecutor completed);
  
    /**
     * Cancel any outstanding work, if possible. Any future calls to schedule should ignore any work.
     */
    void shutdown();
  }
  