package org.apache.maven.index.context;
   
   /*
    * 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.io.IOException;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  import java.util.concurrent.ConcurrentHashMap;
  
  import org.apache.lucene.store.Directory;
  import org.apache.lucene.store.Lock;
  import org.apache.lucene.store.LockFactory;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   *
   * @author Tomas Zezula
   */
  final class TrackingLockFactory
      extends LockFactory
  {
  
      private final LockFactory delegate;
  
      private final Set<TrackingLock> emittedLocks;
  
      TrackingLockFactory( final LockFactory delegate )
      {
          this.delegate = requireNonNull( delegate );
          this.emittedLocks = Collections.newSetFromMap( new ConcurrentHashMap<TrackingLock, Boolean>() );
      }
  
      Set<? extends Lock> getEmittedLocks( String name )
      {
          final Set<Lock> result = new HashSet<>();
          for ( TrackingLock lock : emittedLocks )
          {
              if ( name == null || name.equals( lock.getName() ) )
              {
                  result.add( lock );
              }
          }
          return result;
      }
  
      @Override
      public Lock obtainLock( Directory dir, String lockName )
          throws IOException
      {
          final TrackingLock lck = new TrackingLock( delegate.obtainLock( dir, lockName ), lockName );
          emittedLocks.add( lck );
          return lck;
      }
  
      private final class TrackingLock
          extends Lock
      {
          private final Lock delegate;
  
          private final String name;
  
          TrackingLock( final Lock delegate, final String name )
          {
              this.delegate = requireNonNull( delegate );
              this.name = requireNonNull( name );
          }
  
          String getName()
          {
              return name;
          }
  
          @Override
          public void close()
              throws IOException
          {
              try
              {
                  delegate.close();
              }
             finally
             {
                 emittedLocks.remove( this );
             }
         }
 
         @Override
         public void ensureValid()
             throws IOException
         {
             delegate.ensureValid();
         }
     }
 }