package org.apache.maven.surefire.junitcore.pc;
   
   /*
    * 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.
   */
  
  import org.junit.runner.Computer;
  import org.junit.runner.Description;
  
  import java.util.Collection;
  import java.util.concurrent.Callable;
  import java.util.concurrent.Executors;
  import java.util.concurrent.Future;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.TimeUnit;
  
  /**
   * ParallelComputer extends JUnit {@link Computer} and has a shutdown functionality.
   *
   * @author Tibor Digana (tibor17)
   * @since 2.16
   *
   * @see ParallelComputerBuilder
   */
  public abstract class ParallelComputer extends Computer
  {
      private ScheduledExecutorService shutdownScheduler;
  
      public abstract Collection<Description> shutdown( boolean shutdownNow );
  
      protected final void afterRunQuietly()
      {
          if ( shutdownScheduler != null )
          {
              shutdownScheduler.shutdownNow();
          }
      }
  
      public Future<Collection<Description>> scheduleShutdown( int timeout, TimeUnit unit )
      {
          return getShutdownScheduler().schedule( createShutdownTask( false ), timeout, unit );
      }
  
      public Future<Collection<Description>> scheduleForcedShutdown( int timeout, TimeUnit unit )
      {
          return getShutdownScheduler().schedule( createShutdownTask( true ), timeout, unit );
      }
  
      private ScheduledExecutorService getShutdownScheduler()
      {
          if ( shutdownScheduler == null )
          {
              shutdownScheduler = Executors.newScheduledThreadPool( 2 );
          }
          return shutdownScheduler;
      }
  
      private Callable<Collection<Description>> createShutdownTask( final boolean isForced )
      {
          return new Callable<Collection<Description>>()
          {
              public Collection<Description> call() throws Exception
              {
                  return shutdown( isForced );
              }
          };
      }
  }