package org.eclipse.aether.internal.impl;
   
   /*
    * 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 javax.inject.Inject;
  import javax.inject.Named;
  import javax.inject.Singleton;
  
  import java.util.ArrayList;
  import java.util.concurrent.CopyOnWriteArrayList;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.eclipse.aether.MultiRuntimeException;
  import org.eclipse.aether.impl.RepositorySystemLifecycle;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   *
   */
  @Singleton
  @Named
  public class DefaultRepositorySystemLifecycle
          implements RepositorySystemLifecycle
  {
      private final AtomicBoolean shutdown;
  
      private final CopyOnWriteArrayList<Runnable> onSystemEndedHandlers;
  
      @Inject
      public DefaultRepositorySystemLifecycle()
      {
          this.shutdown = new AtomicBoolean( false );
          this.onSystemEndedHandlers = new CopyOnWriteArrayList<>();
      }
  
      @Override
      public void systemEnded()
      {
          if ( shutdown.compareAndSet( false, true ) )
          {
              final ArrayList<Exception> exceptions = new ArrayList<>();
              for ( Runnable onCloseHandler : onSystemEndedHandlers )
              {
                  try
                  {
                      onCloseHandler.run();
                  }
                  catch ( Exception e )
                  {
                      exceptions.add( e );
                  }
              }
              MultiRuntimeException.mayThrow( "system on-close handler failures", exceptions );
          }
      }
  
      @Override
      public void addOnSystemEndedHandler( Runnable handler )
      {
          requireNonNull( handler, "handler cannot be null" );
          requireNotShutdown();
          onSystemEndedHandlers.add( 0, handler );
      }
  
      private void requireNotShutdown()
      {
          if ( shutdown.get() )
          {
              throw new IllegalStateException( "repository system is already shut down" );
          }
      }
  }