content: /**
   * 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.solr.core;
  
  import java.io.IOException;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.lucene.index.IndexFileNameFilter;
  import org.apache.lucene.store.Directory;
  import org.apache.lucene.store.RAMDirectory;
  
  public class RefCntRamDirectory extends RAMDirectory {
  
    private final AtomicInteger refCount = new AtomicInteger();
  
    public RefCntRamDirectory() {
      super();
      refCount.set(1);
    }
  
    public RefCntRamDirectory(Directory dir) throws IOException {
      this();
  
      IndexFileNameFilter filter = IndexFileNameFilter.getFilter();
      for (String file : dir.listAll()) {
        if (filter.accept(null, file)) {
          dir.copy(this, file, file);
        }
      }
    }
  
    public void incRef() {
      ensureOpen();
      refCount.incrementAndGet();
    }
  
    public void decRef() {
      ensureOpen();
      if (refCount.getAndDecrement() == 1) {
        super.close();
      }
    }
  
    @Override
    public final synchronized void close() {
      decRef();
    }
  
    public boolean isOpen() {
      return isOpen;
    }
  
  }
  