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 java.util.Collection;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Future;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  /**
   * Abstract parallel scheduling strategy in private package.
   * The remaining abstract methods have to be implemented differently
   * depending if the thread pool is shared with other strategies or not.
   *
   * @author Tibor Digana (tibor17)
   * @since 2.16
   *
   * @see SchedulingStrategy
   * @see SharedThreadPoolStrategy
   * @see NonSharedThreadPoolStrategy
   */
  abstract class AbstractThreadPoolStrategy extends SchedulingStrategy {
      private final ExecutorService threadPool;
      private final Collection<Future<?>> futureResults;
      private final AtomicBoolean canSchedule = new AtomicBoolean(true);
  
      AbstractThreadPoolStrategy(ExecutorService threadPool) {
          this(threadPool, null);
      }
  
      AbstractThreadPoolStrategy(ExecutorService threadPool, Collection<Future<?>> futureResults) {
          this.threadPool = threadPool;
          this.futureResults = futureResults;
      }
  
      protected final ExecutorService getThreadPool() {
          return threadPool;
      }
  
      protected final Collection<Future<?>> getFutureResults() {
          return futureResults;
      }
  
      protected final void disable() {
          canSchedule.set(false);
      }
  
      @Override
      public void schedule(Runnable task) {
          if (canSchedule()) {
              Future<?> futureResult = threadPool.submit(task);
              if (futureResults != null) {
                  futureResults.add(futureResult);
              }
          }
      }
  
      @Override
      protected boolean stop() {
          boolean wasRunning = canSchedule.getAndSet(false);
          if (threadPool.isShutdown()) {
              wasRunning = false;
          } else {
              threadPool.shutdown();
          }
          return wasRunning;
      }
  
      @Override
      protected boolean stopNow() {
          boolean wasRunning = canSchedule.getAndSet(false);
          if (threadPool.isShutdown()) {
              wasRunning = false;
          } else {
              threadPool.shutdownNow();
          }
          return wasRunning;
      }
  
      @Override
      protected void setDefaultShutdownHandler(Scheduler.ShutdownHandler handler) {
         if (threadPool instanceof ThreadPoolExecutor) {
             ThreadPoolExecutor pool = (ThreadPoolExecutor) threadPool;
             handler.setRejectedExecutionHandler(pool.getRejectedExecutionHandler());
             pool.setRejectedExecutionHandler(handler);
         }
     }
 
     @Override
     public final boolean canSchedule() {
         return canSchedule.get();
     }
 }