/*
    * 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.maven.index.context;
  
  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();
          }
      }
  }